// SPDX-License-Identifier: AGPL-3.0-or-later /* PASST - Plug A Simple Socket Transport * for qemu/UNIX domain socket mode * * PASTA - Pack A Subtle Tap Abstraction * for network namespace/tap device mode * * tcp.c - TCP L2-L4 translation state machine * * Copyright (c) 2020-2021 Red Hat GmbH * Author: Stefano Brivio */ /** * DOC: Theory of Operation * * * PASST mode * ========== * * This implementation maps TCP traffic between a single L2 interface (tap) and * native TCP (L4) sockets, mimicking and reproducing as closely as possible the * inferred behaviour of applications running on a guest, connected via said L2 * interface. Four connection flows are supported: * - from the local host to the guest behind the tap interface: * - this is the main use case for proxies in service meshes * - we bind to configured local ports, and relay traffic between L4 sockets * with local endpoints and the L2 interface * - from remote hosts to the guest behind the tap interface: * - this might be needed for services that need to be addressed directly, * and typically configured with special port forwarding rules (which are * not needed here) * - we also relay traffic between L4 sockets with remote endpoints and the L2 * interface * - from the guest to the local host: * - this is not observed in practice, but implemented for completeness and * transparency * - from the guest to external hosts: * - this might be needed for applications running on the guest that need to * directly access internet services (e.g. NTP) * * Relevant goals are: * - transparency: sockets need to behave as if guest applications were running * directly on the host. This is achieved by: * - avoiding port and address translations whenever possible * - mirroring TCP dynamics by observation of socket parameters (TCP_INFO * socket option) and TCP headers of packets coming from the tap interface, * reapplying those parameters in both flow directions (including TCP_MSS, * TCP_WINDOW_CLAMP socket options) * - simplicity: only a small subset of TCP logic is implemented here and * delegated as much as possible to the TCP implementations of guest and host * kernel. This is achieved by: * - avoiding a complete TCP stack reimplementation, with a modified TCP state * machine focused on the translation of observed states instead * - mirroring TCP dynamics as described above and hence avoiding the need for * segmentation, explicit queueing, and reassembly of segments * - security: * - no dynamic memory allocation is performed * - TODO: synflood protection * * Portability is limited by usage of Linux-specific socket options. * * * Limits * ------ * * To avoid the need for dynamic memory allocation, a maximum, reasonable amount * of connections is defined by MAX_TAP_CONNS below (currently 128k). * * Data needs to linger on sockets as long as it's not acknowledged by the * guest, and is read using MSG_PEEK into preallocated static buffers sized * to the maximum supported window, 64MiB ("discard" buffer, for already-sent * data) plus a number of maximum-MSS-sized buffers. This imposes a practical * limitation on window scaling, that is, the maximum factor is 1024. Larger * factors will be accepted, but resulting, larger values are never advertised * to the other side, and not used while queueing data. * * * Ports * ----- * * To avoid the need for ad-hoc configuration of port forwarding or allowed * ports, listening sockets can be opened and bound to all unbound ports on the * host, as far as process capabilities allow. This service needs to be started * after any application proxy that needs to bind to local ports. Mapped ports * can also be configured explicitly. * * No port translation is needed for connections initiated remotely or by the * local host: source port from socket is reused while establishing connections * to the guest. * * For connections initiated by the guest, it's not possible to force the same * source port as connections are established by the host kernel: that's the * only port translation needed. * * * Connection tracking and storage * ------------------------------- * * Connections are tracked by the @tt array of struct tcp_tap_conn, containing * addresses, ports, TCP states and parameters. This is statically allocated and * indexed by an arbitrary connection number. The array is compacted whenever a * connection is closed, by remapping the highest connection index in use to the * one freed up. * * References used for the epoll interface report the connection index used for * the @tt array. * * IPv4 addresses are stored as IPv4-mapped IPv6 addresses to avoid the need for * separate data structures depending on the protocol version. * * - Inbound connection requests (to the guest) are mapped using the triple * < source IP address, source port, destination port > * - Outbound connection requests (from the guest) are mapped using the triple * < destination IP address, destination port, source port > * where the source port is the one used by the guest, not the one used by the * corresponding host socket * * * Initialisation * -------------- * * Up to 2^15 + 2^14 listening sockets (excluding ephemeral ports, repeated for * IPv4 and IPv6) can be opened and bound to wildcard addresses. Some will fail * to bind (for low ports, or ports already bound, e.g. by a proxy). These are * added to the epoll list, with no separate storage. * * * States and events * ----------------- * * These states apply to connected sockets only, listening sockets are always * open after initialisation, in LISTEN state. A single state is maintained for * both sides of the connection, and some states are omitted as they are already * handled by host kernel and guest. * * - CLOSED no connection * No associated events: this is always a final state, new connections * directly start from TAP_SYN_SENT or SOCK_SYN_SENT described below. * * - TAP_SYN_SENT connect() in progress, triggered from tap * - connect() completes SYN,ACK to tap > TAP_SYN_RCVD * - connect() aborts RST to tap, close socket > CLOSED * * - SOCK_SYN_SENT new connected socket, SYN sent to tap * - SYN,ACK from tap ACK to tap > ESTABLISHED * - SYN,ACK timeout RST to tap, close socket > CLOSED * * - TAP_SYN_RCVD connect() completed, SYN,ACK sent to tap * - FIN from tap write shutdown > FIN_WAIT_1 * - ACK from tap > ESTABLISHED * - ACK timeout RST to tap, close socket > CLOSED * * - ESTABLISHED connection established, ready for data * - EPOLLRDHUP read shutdown > ESTABLISHED_SOCK_FIN * - FIN from tap write shutdown > FIN_WAIT_1 * - EPOLLHUP RST to tap, close socket > CLOSED * - data timeout read shutdown, FIN to tap > * ESTABLISHED_SOCK_FIN_SENT * * - ESTABLISHED_SOCK_FIN socket closing connection, reading half closed * - zero-sized socket read FIN,ACK to tap > ESTABLISHED_SOCK_FIN_SENT * * - ESTABLISHED_SOCK_FIN_SENT socket closing connection, FIN sent to tap * - ACK (for FIN) from tap > CLOSE_WAIT * - tap ACK timeout RST to tap, close socket > CLOSED * * - CLOSE_WAIT socket closing connection, ACK from tap * - FIN from tap write shutdown > LAST_ACK * - data timeout RST to tap, close socket > CLOSED * * - LAST_ACK socket started close, tap completed it * - any event from socket ACK to tap, close socket > CLOSED * - ACK timeout RST to tap, close socket > CLOSED * * - FIN_WAIT_1 tap closing connection, FIN sent to socket * - EPOLLRDHUP FIN,ACK to tap, shutdown > FIN_WAIT_1_SOCK_FIN * - socket timeout RST to tap, close socket > CLOSED * * - FIN_WAIT_1_SOCK_FIN tap closing connection, FIN received from socket * - ACK from tap close socket > CLOSED * - tap ACK timeout RST to tap, close socket > CLOSED * * - from any state * - RST from tap close socket > CLOSED * - socket error RST to tap, close socket > CLOSED * * Connection setup * ---------------- * * - inbound connection (from socket to guest): on accept() from listening * socket, the new socket is mapped in connection tracking table, and * three-way handshake initiated towards the guest, advertising MSS and window * size and scaling from socket parameters * - outbound connection (from guest to socket): on SYN segment from guest, a * new socket is created and mapped in connection tracking table, setting * MSS and window clamping from header and option of the observed SYN segment * * * Aging and timeout * ----------------- * * A bitmap of TCP_MAX_CONNS bits indicate the connections subject to timed * events based on states: * - SOCK_SYN_SENT: after a 2MSL (240s) timeout waiting for a SYN,ACK segment * from tap expires, connection is reset (RST to tap, socket closed) * - TAP_SYN_RCVD: after a 2MSL (240s) timeout waiting for an ACK segment from * tap expires, connection is reset (RST to tap, socket closed) * - TAP_SYN_SENT: connect() is pending, timeout is handled implicitly by * connect() timeout, connection will be reset in case * - ESTABLISHED, ESTABLISHED_SOCK_FIN: if an ACK segment to tap is pending, * bytes acknowledged by socket endpoint are checked every 50ms (one quarter * of current TCP_DELACK_MAX on Linux) * - ESTABLISHED, ESTABLISHED_SOCK_FIN: after a timeout of 3s (TODO: implement * requirements from RFC 6298) waiting for an ACK segment from tap expires, * data from socket queue is retransmitted starting from the last ACK sequence * - ESTABLISHED, ESTABLISHED_SOCK_FIN: after a two hours (current * TCP_KEEPALIVE_TIME on Linux) timeout waiting for any activity expires, * connection is reset (RST to tap, socket closed) * - ESTABLISHED_SOCK_FIN: after a 2MSL (240s) timeout waiting for an ACK * segment from tap expires, connection is reset (RST to tap, socket closed) * - CLOSE_WAIT: after a 2MSL (240s) timeout waiting for a FIN segment from tap * expires, connection is reset (RST to tap, socket closed) * - FIN_WAIT_1: after a 2MSL (240s) timeout waiting for an ACK segment from * socet expires, connection is reset (RST to tap, socket closed) * - FIN_WAIT_1_SOCK_FIN: after a 2MSL (240s) timeout waiting for an ACK segment * from tap expires, connection is reset (RST to tap, socket closed) * - LAST_ACK: after a 2MSL (240s) timeout waiting for an ACK segment from * socket expires, connection is reset (RST to tap, socket closed) * * * Data flows (from ESTABLISHED, ESTABLISHED_SOCK_FIN states) * ---------------------------------------------------------- * * @seq_to_tap: next sequence for packets to tap * @seq_ack_from_tap: last ACK number received from tap * @seq_from_tap: next sequence for packets from tap (not actually sent) * @seq_ack_to_tap: last ACK number sent to tap * * @seq_init_from_tap: initial sequence number from tap * * @wnd_from_tap: last window size received from tap, scaled * * - from socket to tap: * - on new data from socket: * - peek into buffer * - send data to tap: * - starting at offset (@seq_to_tap - @seq_ack_from_tap) * - in MSS-sized segments * - increasing @seq_to_tap at each segment * - up to window (until @seq_to_tap - @seq_ack_from_tap <= @wnd_from_tap) * - mark socket in bitmap for periodic ACK check, set @last_ts_to_tap * - on read error, send RST to tap, close socket * - on zero read, send FIN to tap, enter ESTABLISHED_SOCK_FIN * - on ACK from tap: * - set @ts_ack_tap * - check if it's the second duplicated ACK * - consume buffer by difference between new ack_seq and @seq_ack_from_tap * - update @seq_ack_from_tap from ack_seq in header * - on two duplicated ACKs, reset @seq_to_tap to @seq_ack_from_tap, and * resend with steps listed above * - set TCP_WINDOW_CLAMP from TCP header from tap * - on @seq_ack_from_tap == @seq_to_tap, mark in bitmap, umark otherwise * - periodically: * - if @seq_ack_from_tap < @seq_to_tap and the retransmission timer * (TODO: implement requirements from RFC 6298, currently 3s fixed) from * @ts_tap_from_ack elapsed, reset @seq_to_tap to @seq_ack_from_tap, and * resend data with the steps listed above * * - from tap to socket: * - on packet from tap: * - set @ts_tap_ack * - set TCP_WINDOW_CLAMP from TCP header from tap * - check seq from header against @seq_from_tap, if data is missing, send * two ACKs with number @seq_ack_to_tap, discard packet * - otherwise queue data to socket, set @seq_from_tap to seq from header * plus payload length * - in ESTABLISHED state, send ACK to tap as soon as we queue to the * socket. In other states, query socket for TCP_INFO, set * @seq_ack_to_tap to (tcpi_bytes_acked + @seq_init_from_tap) % 2^32 and * send ACK to tap * * * PASTA mode * ========== * * For traffic directed to TCP ports configured for mapping to the tuntap device * in the namespace, and for non-local traffic coming from the tuntap device, * the implementation is identical as the PASST mode described in the previous * section. * * For local traffic directed to TCP ports configured for direct mapping between * namespaces, the implementation is substantially simpler: packets are directly * translated between L4 sockets using a pair of splice() syscalls. These * connections are tracked in the @ts array of struct tcp_splice_conn, using * these states: * * - CLOSED: no connection * - SPLICE_ACCEPTED: accept() on the listening socket succeeded * - SPLICE_CONNECT: connect() issued in the destination namespace * - SPLICE_ESTABLISHED: connect() succeeded, packets are transferred * - SPLICE_FIN_FROM: FIN (EPOLLRDHUP) seen from originating socket * - SPLICE_FIN_TO: FIN (EPOLLRDHUP) seen from connected socket * - SPLICE_FIN_BOTH: FIN (EPOLLRDHUP) seen from both sides */ #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "checksum.h" #include "util.h" #include "passt.h" #include "tap.h" #include "siphash.h" #include "pcap.h" #include "conf.h" #define MAX_TAP_CONNS (128 * 1024) #define MAX_SPLICE_CONNS (128 * 1024) #define TCP_TAP_FRAMES 8 #define MAX_PIPE_SIZE (2 * 1024 * 1024) #define TCP_HASH_TABLE_LOAD 70 /* % */ #define TCP_HASH_TABLE_SIZE (MAX_TAP_CONNS * 100 / \ TCP_HASH_TABLE_LOAD) #define MAX_WS 10 #define MAX_WINDOW (1 << (16 + (MAX_WS))) #define MSS_DEFAULT 536 #define WINDOW_DEFAULT 14600 /* RFC 6928 */ #define SYN_TIMEOUT 240000 /* ms */ #define ACK_TIMEOUT 2000 #define ACK_INTERVAL 50 #define ACT_TIMEOUT 7200000 #define FIN_TIMEOUT 240000 #define LAST_ACK_TIMEOUT 240000 #define TCP_SOCK_POOL_SIZE 256 #define TCP_SOCK_POOL_TSH 128 /* Refill in ns if > x used */ #define TCP_SPLICE_PIPE_POOL_SIZE 256 #define REFILL_INTERVAL 1000 #define PORT_DETECT_INTERVAL 1000 /* We need to include for tcpi_bytes_acked, instead of * , but that doesn't include a definition for SOL_TCP */ #define SOL_TCP IPPROTO_TCP #define SEQ_LE(a, b) ((b) - (a) < MAX_WINDOW) #define SEQ_LT(a, b) ((b) - (a) - 1 < MAX_WINDOW) #define SEQ_GE(a, b) ((a) - (b) < MAX_WINDOW) #define SEQ_GT(a, b) ((a) - (b) - 1 < MAX_WINDOW) enum tcp_state { CLOSED = 0, TAP_SYN_SENT, SOCK_SYN_SENT, TAP_SYN_RCVD, ESTABLISHED, ESTABLISHED_SOCK_FIN, ESTABLISHED_SOCK_FIN_SENT, CLOSE_WAIT, LAST_ACK, FIN_WAIT_1, FIN_WAIT_1_SOCK_FIN, SPLICE_ACCEPTED, SPLICE_CONNECT, SPLICE_ESTABLISHED, SPLICE_FIN_FROM, SPLICE_FIN_TO, SPLICE_FIN_BOTH, }; #define TCP_STATE_STR_SIZE (SPLICE_FIN_BOTH + 1) static char *tcp_state_str[TCP_STATE_STR_SIZE] __attribute((__unused__)) = { "CLOSED", "TAP_SYN_SENT", "SOCK_SYN_SENT", "TAP_SYN_RCVD", "ESTABLISHED", "ESTABLISHED_SOCK_FIN", "ESTABLISHED_SOCK_FIN_SENT", "CLOSE_WAIT", "LAST_ACK", "FIN_WAIT_1", "FIN_WAIT_1_SOCK_FIN", "SPLICE_ACCEPTED", "SPLICE_CONNECT", "SPLICE_ESTABLISHED", "SPLICE_FIN_FROM", "SPLICE_FIN_TO", "SPLICE_FIN_BOTH", }; #define FIN (1 << 0) #define SYN (1 << 1) #define RST (1 << 2) #define ACK (1 << 4) /* Flags for internal usage */ #define UPDATE_WINDOW (1 << 5) #define DUP_ACK (1 << 6) #define FORCE_ACK (1 << 7) #define OPT_EOL 0 #define OPT_NOP 1 #define OPT_MSS 2 #define OPT_MSS_LEN 4 #define OPT_WS 3 #define OPT_WS_LEN 3 #define OPT_SACKP 4 #define OPT_SACK 5 #define OPT_TS 8 struct tcp_tap_conn; /** * struct tcp_tap_conn - Descriptor for a TCP connection via tap (not spliced) * @next: Pointer to next item in hash chain, if any * @sock: Socket descriptor number * @hash_bucket: Bucket index in connection lookup hash table * @a.a6: IPv6 remote address, can be IPv4-mapped * @a.a4.zero: Zero prefix for IPv4-mapped, see RFC 6890, Table 20 * @a.a4.one: Ones prefix for IPv4-mapped * @a.a4.a: IPv4 address * @tap_port: Guest-facing tap port * @sock_port: Remote, socket-facing port * @state: TCP connection state * @seq_to_tap: Next sequence for packets to tap * @seq_ack_from_tap: Last ACK number received from tap * @seq_from_tap: Next sequence for packets from tap (not actually sent) * @seq_ack_to_tap: Last ACK number sent to tap * @seq_dup_ack: Last duplicate ACK number sent to tap * @seq_init_from_tap: Initial sequence number from tap * @seq_init_from_tap: Initial sequence number to tap * @ws_tap: Window scaling factor from tap * @ws: Window scaling factor * @wnd_from_tap: Last window size received from tap, scaled * @wnd_to_tap: Socket-side sending window, advertised to tap * @window_clamped: Window was clamped on socket at least once * @ts_sock_act: Last activity timestamp from socket for timeout purposes * @ts_tap_act: Last activity timestamp from tap for timeout purposes * @ts_ack_from_tap: Last ACK segment timestamp from tap * @ts_ack_to_tap: Last ACK segment timestamp to tap * @tap_data_noack: Last unacked data to tap, set to { 0, 0 } on ACK * @mss_guest: Maximum segment size advertised by guest * @events: epoll events currently enabled for socket */ struct tcp_tap_conn { struct tcp_tap_conn *next; int sock; int hash_bucket; union { struct in6_addr a6; struct { uint8_t zero[10]; uint8_t one[2]; struct in_addr a; } a4; } a; in_port_t tap_port; in_port_t sock_port; enum tcp_state state; uint32_t seq_to_tap; uint32_t seq_ack_from_tap; uint32_t seq_from_tap; uint32_t seq_ack_to_tap; uint32_t seq_dup_ack; uint32_t seq_init_from_tap; uint32_t seq_init_to_tap; uint16_t ws_tap; uint16_t ws; uint32_t wnd_from_tap; uint32_t wnd_to_tap; int window_clamped; int snd_buf; struct timespec ts_sock_act; struct timespec ts_tap_act; struct timespec ts_ack_from_tap; struct timespec ts_ack_to_tap; struct timespec tap_data_noack; int mss_guest; uint32_t events; }; /** * struct tcp_splice_conn - Descriptor for a spliced TCP connection * @from: File descriptor number of socket for accepted connection * @pipe_from_to: Pipe ends for splice() from @from to @to * @to: File descriptor number of peer connected socket * @pipe_to_from: Pipe ends for splice() from @to to @from * @state: TCP connection state */ struct tcp_splice_conn { int from; int pipe_from_to[2]; int to; int pipe_to_from[2]; enum tcp_state state; int from_fin_sent; int to_fin_sent; int v6; uint64_t from_read; uint64_t from_written; uint64_t to_read; uint64_t to_written; }; /* Port re-mappings as delta, indexed by original destination port */ static in_port_t tcp_port_delta_to_tap [USHRT_MAX]; static in_port_t tcp_port_delta_to_init [USHRT_MAX]; /* Listening sockets, used for automatic port forwarding in pasta mode only */ static int tcp_sock_init_lo [USHRT_MAX][IP_VERSIONS]; static int tcp_sock_init_ext [USHRT_MAX][IP_VERSIONS]; static int tcp_sock_ns [USHRT_MAX][IP_VERSIONS]; /** * tcp_remap_to_tap() - Set delta for port translation toward guest/tap * @port: Original destination port, host order * @delta: Delta to be added to original destination port */ void tcp_remap_to_tap(in_port_t port, in_port_t delta) { tcp_port_delta_to_tap[port] = delta; } /** * tcp_remap_to_tap() - Set delta for port translation toward init namespace * @port: Original destination port, host order * @delta: Delta to be added to original destination port */ void tcp_remap_to_init(in_port_t port, in_port_t delta) { tcp_port_delta_to_init[port] = delta; } /* Static buffers */ /** * tcp4_l2_buf_t - Pre-cooked IPv4 packet buffers for tap connections * @psum: Partial IP header checksum (excluding tot_len and saddr) * @tsum: Partial TCP header checksum (excluding length and saddr) * @pad: Align TCP header to 32 bytes, for AVX2 checksum calculation only * @vnet_len: 4-byte qemu vnet buffer length descriptor, only for passt mode * @eh: Pre-filled Ethernet header * @iph: Pre-filled IP header (except for tot_len and saddr) * @uh: Headroom for TCP header * @data: Storage for TCP payload */ __extension__ static struct tcp4_l2_buf_t { uint32_t psum; /* 0 */ uint32_t tsum; /* 4 */ #ifdef __AVX2__ uint8_t pad[18]; /* 8, align th to 32 bytes */ #endif uint32_t vnet_len; /* 26 */ struct ethhdr eh; /* 30 */ struct iphdr iph; /* 44 */ struct tcphdr th; /* 64 */ uint8_t data[USHRT_MAX - sizeof(struct tcphdr)]; #ifdef __AVX2__ } __attribute__ ((packed, aligned(32))) #else } __attribute__ ((packed, aligned(__alignof__(unsigned int)))) #endif tcp4_l2_buf[TCP_TAP_FRAMES] = { [ 0 ... TCP_TAP_FRAMES - 1 ] = { 0, 0, #ifdef __AVX2__ { 0 }, #endif 0, L2_BUF_ETH_IP4_INIT, L2_BUF_IP4_INIT(IPPROTO_TCP), { .doff = sizeof(struct tcphdr) / 4, .ack = 1 }, { 0 }, }, }; static int tcp4_l2_buf_mss; static int tcp4_l2_buf_mss_nr_set; static int tcp4_l2_buf_mss_tap; static int tcp4_l2_buf_mss_tap_nr_set; /** * tcp6_l2_buf_t - Pre-cooked IPv6 packet buffers for tap connections * @pad: Align IPv6 header for checksum calculation to 32B (AVX2) or 4B * @vnet_len: 4-byte qemu vnet buffer length descriptor, only for passt mode * @eh: Pre-filled Ethernet header * @ip6h: Pre-filled IP header (except for payload_len and addresses) * @th: Headroom for TCP header * @data: Storage for TCP payload */ __extension__ struct tcp6_l2_buf_t { #ifdef __AVX2__ uint8_t pad[14]; /* 0 align ip6h to 32 bytes */ #else uint8_t pad[2]; /* align ip6h to 4 bytes 0 */ #endif uint32_t vnet_len; /* 14 2 */ struct ethhdr eh; /* 18 6 */ struct ipv6hdr ip6h; /* 32 20 */ struct tcphdr th; /* 72 60 */ uint8_t data[USHRT_MAX - (sizeof(struct ipv6hdr) + sizeof(struct tcphdr))]; #ifdef __AVX2__ } __attribute__ ((packed, aligned(32))) #else } __attribute__ ((packed, aligned(__alignof__(unsigned int)))) #endif tcp6_l2_buf[TCP_TAP_FRAMES] = { [ 0 ... TCP_TAP_FRAMES - 1 ] = { { 0 }, 0, L2_BUF_ETH_IP6_INIT, L2_BUF_IP6_INIT(IPPROTO_TCP), { .doff = sizeof(struct tcphdr) / 4, .ack = 1 }, { 0 }, }, }; static int tcp6_l2_buf_mss; static int tcp6_l2_buf_mss_nr_set; static int tcp6_l2_buf_mss_tap; static int tcp6_l2_buf_mss_tap_nr_set; /* recvmsg()/sendmsg() data for tap */ static struct iovec tcp4_l2_iov_sock [TCP_TAP_FRAMES + 1]; static struct iovec tcp6_l2_iov_sock [TCP_TAP_FRAMES + 1]; static char tcp_buf_discard [MAX_WINDOW]; static struct iovec tcp4_l2_iov_tap [TCP_TAP_FRAMES]; static struct iovec tcp6_l2_iov_tap [TCP_TAP_FRAMES]; static struct msghdr tcp4_l2_mh_sock; static struct msghdr tcp6_l2_mh_sock; __extension__ static struct mmsghdr tcp_l2_mh_tap [TCP_TAP_FRAMES] = { [ 0 ... TCP_TAP_FRAMES - 1 ] = { .msg_hdr.msg_iovlen = 1, }, }; /* sendmsg() to socket */ static struct iovec tcp_tap_iov [UIO_MAXIOV]; /* SO_RCVLOWAT set on source ([0]) or destination ([1]) socket, and activity */ static uint8_t splice_rcvlowat_set[MAX_SPLICE_CONNS / 8][2]; static uint8_t splice_rcvlowat_act[MAX_SPLICE_CONNS / 8][2]; /* TCP connections */ static struct tcp_tap_conn tt[MAX_TAP_CONNS]; static struct tcp_splice_conn ts[MAX_SPLICE_CONNS]; /* Table for lookup from remote address, local port, remote port */ static struct tcp_tap_conn *tt_hash[TCP_HASH_TABLE_SIZE]; /* Pools for pre-opened sockets and pipes */ static int splice_pipe_pool [TCP_SPLICE_PIPE_POOL_SIZE][2][2]; static int init_sock_pool4 [TCP_SOCK_POOL_SIZE]; static int init_sock_pool6 [TCP_SOCK_POOL_SIZE]; static int ns_sock_pool4 [TCP_SOCK_POOL_SIZE]; static int ns_sock_pool6 [TCP_SOCK_POOL_SIZE]; /** * tcp_tap_state() - Set given TCP state for tap connection, report to stderr * @conn: Connection pointer * @state: New TCP state to be set */ static void tcp_tap_state(struct tcp_tap_conn *conn, enum tcp_state state) { debug("TCP: socket %i: %s -> %s", conn->sock, tcp_state_str[conn->state], tcp_state_str[state]); conn->state = state; } /** * tcp_splice_state() - Set state for spliced connection, report to stderr * @conn: Connection pointer * @state: New TCP state to be set */ static void tcp_splice_state(struct tcp_splice_conn *conn, enum tcp_state state) { debug("TCP: index %i: %s -> %s", conn - ts, tcp_state_str[conn->state], tcp_state_str[state]); conn->state = state; } /** * tcp_sock_set_bufsize() - Set SO_RCVBUF and SO_SNDBUF to maximum values * @s: Socket, can be -1 to avoid check in the caller */ static void tcp_sock_set_bufsize(int s) { int v = INT_MAX / 2; /* Kernel clamps and rounds, no need to check */ if (s == -1) return; setsockopt(s, SOL_SOCKET, SO_RCVBUF, &v, sizeof(v)); setsockopt(s, SOL_SOCKET, SO_SNDBUF, &v, sizeof(v)); } /** * tcp_update_check_ip4() - Update IPv4 with variable parts from stored one * @buf: L2 packet buffer with final IPv4 header */ static void tcp_update_check_ip4(struct tcp4_l2_buf_t *buf) { uint32_t sum = buf->psum; sum += buf->iph.tot_len; sum += (buf->iph.saddr >> 16) & 0xffff; sum += buf->iph.saddr & 0xffff; buf->iph.check = (uint16_t)~csum_fold(sum); } /** * tcp_update_check_tcp4() - Update TCP checksum from stored one * @buf: L2 packet buffer with final IPv4 header */ static void tcp_update_check_tcp4(struct tcp4_l2_buf_t *buf) { uint16_t tlen = ntohs(buf->iph.tot_len) - 20; uint32_t sum = buf->tsum; sum += (buf->iph.saddr >> 16) & 0xffff; sum += buf->iph.saddr & 0xffff; sum += htons(ntohs(buf->iph.tot_len) - 20); buf->th.check = 0; buf->th.check = csum(&buf->th, tlen, sum); } /** * tcp_update_check_tcp6() - Calculate TCP checksum for IPv6 * @buf: L2 packet buffer with final IPv6 header */ static void tcp_update_check_tcp6(struct tcp6_l2_buf_t *buf) { int len = ntohs(buf->ip6h.payload_len) + sizeof(struct ipv6hdr); buf->ip6h.hop_limit = IPPROTO_TCP; buf->ip6h.version = 0; buf->ip6h.nexthdr = 0; buf->th.check = 0; buf->th.check = csum(&buf->ip6h, len, 0); buf->ip6h.hop_limit = 255; buf->ip6h.version = 6; buf->ip6h.nexthdr = IPPROTO_TCP; } /** * tcp_update_l2_buf() - Update L2 buffers with Ethernet and IPv4 addresses * @eth_d: Ethernet destination address, NULL if unchanged * @eth_s: Ethernet source address, NULL if unchanged * @ip_da: Pointer to IPv4 destination address, NULL if unchanged */ void tcp_update_l2_buf(unsigned char *eth_d, unsigned char *eth_s, uint32_t *ip_da) { int i; for (i = 0; i < TCP_TAP_FRAMES; i++) { struct tcp4_l2_buf_t *b4 = &tcp4_l2_buf[i]; struct tcp6_l2_buf_t *b6 = &tcp6_l2_buf[i]; if (eth_d) { memcpy(b4->eh.h_dest, eth_d, ETH_ALEN); memcpy(b6->eh.h_dest, eth_d, ETH_ALEN); } if (eth_s) { memcpy(b4->eh.h_source, eth_s, ETH_ALEN); memcpy(b6->eh.h_source, eth_s, ETH_ALEN); } if (ip_da) { b4->iph.daddr = *ip_da; if (!i) { b4->iph.saddr = 0; b4->iph.tot_len = 0; b4->iph.check = 0; b4->psum = sum_16b(&b4->iph, 20); b4->tsum = ((*ip_da >> 16) & 0xffff) + (*ip_da & 0xffff) + htons(IPPROTO_TCP); } else { b4->psum = tcp4_l2_buf[0].psum; b4->tsum = tcp4_l2_buf[0].tsum; } } } } /** * tcp_sock4_iov_init() - Initialise scatter-gather L2 buffers for IPv4 sockets */ static void tcp_sock4_iov_init(void) { struct iovec *iov; int i; tcp4_l2_iov_sock[0].iov_base = tcp_buf_discard; for (i = 0, iov = tcp4_l2_iov_sock + 1; i < TCP_TAP_FRAMES; i++, iov++) { iov->iov_base = &tcp4_l2_buf[i].data; iov->iov_len = MSS_DEFAULT; } tcp4_l2_mh_sock.msg_iov = tcp4_l2_iov_sock; for (i = 0, iov = tcp4_l2_iov_tap; i < TCP_TAP_FRAMES; i++, iov++) { iov->iov_base = &tcp4_l2_buf[i].vnet_len; iov->iov_len = MSS_DEFAULT; } } /** * tcp_sock6_iov_init() - Initialise scatter-gather L2 buffers for IPv6 sockets */ static void tcp_sock6_iov_init(void) { struct iovec *iov; int i; tcp6_l2_iov_sock[0].iov_base = tcp_buf_discard; for (i = 0, iov = tcp6_l2_iov_sock + 1; i < TCP_TAP_FRAMES; i++, iov++) { iov->iov_base = &tcp6_l2_buf[i].data; iov->iov_len = MSS_DEFAULT; } tcp6_l2_mh_sock.msg_iov = tcp6_l2_iov_sock; for (i = 0, iov = tcp6_l2_iov_tap; i < TCP_TAP_FRAMES; i++, iov++) { iov->iov_base = &tcp6_l2_buf[i].vnet_len; iov->iov_len = MSS_DEFAULT; } } /** * tcp_opt_get() - Get option, and value if any, from TCP header * @th: Pointer to TCP header * @len: Length of buffer, including TCP header * @__type: Option type to look for * @__optlen: Optional, filled with option length if passed * @__value: Optional, set to start of option value if passed * * Return: Option value, meaningful for up to 4 bytes, -1 if not found */ static int tcp_opt_get(struct tcphdr *th, size_t len, uint8_t __type, uint8_t *__optlen, char **__value) { uint8_t type, optlen; char *p; if (len > th->doff * 4) len = th->doff * 4; len -= sizeof(*th); p = (char *)(th + 1); for (; len >= 2; p += optlen, len -= optlen) { switch (*p) { case OPT_EOL: return -1; case OPT_NOP: optlen = 1; break; default: type = *(p++); optlen = *(p++) - 2; len -= 2; if (type != __type) break; if (__optlen) *__optlen = optlen; if (__value) *__value = p; switch (optlen) { case 0: return 0; case 1: return *p; case 2: return ntohs(*(uint16_t *)p); default: return ntohl(*(uint32_t *)p); } } } return -1; } /** * tcp_hash_match() - Check if a connection entry matches address and ports * @conn: Connection entry to match against * @af: Address family, AF_INET or AF_INET6 * @addr: Remote address, pointer to sin_addr or sin6_addr * @tap_port: tap-facing port * @sock_port: Socket-facing port * * Return: 1 on match, 0 otherwise */ static int tcp_hash_match(struct tcp_tap_conn *conn, int af, void *addr, in_port_t tap_port, in_port_t sock_port) { if (af == AF_INET && IN6_IS_ADDR_V4MAPPED(&conn->a.a6) && !memcmp(&conn->a.a4.a, addr, sizeof(conn->a.a4.a)) && conn->tap_port == tap_port && conn->sock_port == sock_port) return 1; if (af == AF_INET6 && !memcmp(&conn->a.a6, addr, sizeof(conn->a.a6)) && conn->tap_port == tap_port && conn->sock_port == sock_port) return 1; return 0; } /** * tcp_hash() - Calculate hash value for connection given address and ports * @c: Execution context * @af: Address family, AF_INET or AF_INET6 * @addr: Remote address, pointer to sin_addr or sin6_addr * @tap_port: tap-facing port * @sock_port: Socket-facing port * * Return: hash value, already modulo size of the hash table */ static unsigned int tcp_hash(struct ctx *c, int af, void *addr, in_port_t tap_port, in_port_t sock_port) { uint64_t b = 0; if (af == AF_INET) { struct { struct in_addr addr; in_port_t tap_port; in_port_t sock_port; } __attribute__((__packed__)) in = { .addr = *(struct in_addr *)addr, .tap_port = tap_port, .sock_port = sock_port, }; b = siphash_8b((uint8_t *)&in, c->tcp.hash_secret); } else if (af == AF_INET6) { struct { struct in6_addr addr; in_port_t tap_port; in_port_t sock_port; } __attribute__((__packed__)) in = { .addr = *(struct in6_addr *)addr, .tap_port = tap_port, .sock_port = sock_port, }; b = siphash_20b((uint8_t *)&in, c->tcp.hash_secret); } return (unsigned int)(b % TCP_HASH_TABLE_SIZE); } /** * tcp_hash_insert() - Insert connection into hash table, chain link * @c: Execution context * @conn: Connection pointer * @af: Address family, AF_INET or AF_INET6 * @addr: Remote address, pointer to sin_addr or sin6_addr */ static void tcp_hash_insert(struct ctx *c, struct tcp_tap_conn *conn, int af, void *addr) { int b; b = tcp_hash(c, af, addr, conn->tap_port, conn->sock_port); conn->next = tt_hash[b]; tt_hash[b] = conn; conn->hash_bucket = b; debug("TCP: hash table insert: index %i, sock %i, bucket: %i, next: %p", conn - tt, conn->sock, b, conn->next); } /** * tcp_hash_remove() - Drop connection from hash table, chain unlink * @conn: Connection pointer */ static void tcp_hash_remove(struct tcp_tap_conn *conn) { struct tcp_tap_conn *entry, *prev = NULL; int b = conn->hash_bucket; for (entry = tt_hash[b]; entry; prev = entry, entry = entry->next) { if (entry == conn) { if (prev) prev->next = conn->next; else tt_hash[b] = conn->next; break; } } debug("TCP: hash table remove: index %i, sock %i, bucket: %i, new: %p", conn - tt, conn->sock, b, prev ? prev->next : tt_hash[b]); } /** * tcp_hash_update() - Update pointer for given connection * @old: Old connection pointer * @new: New connection pointer */ static void tcp_hash_update(struct tcp_tap_conn *old, struct tcp_tap_conn *new) { struct tcp_tap_conn *entry, *prev = NULL; int b = old->hash_bucket; for (entry = tt_hash[b]; entry; prev = entry, entry = entry->next) { if (entry == old) { if (prev) prev->next = new; else tt_hash[b] = new; break; } } debug("TCP: hash table update: old index %i, new index %i, sock %i, " "bucket: %i, old: %p, new: %p", old - tt, new - tt, new->sock, b, old, new); } /** * tcp_hash_lookup() - Look up connection given remote address and ports * @c: Execution context * @af: Address family, AF_INET or AF_INET6 * @addr: Remote address, pointer to sin_addr or sin6_addr * @tap_port: tap-facing port * @sock_port: Socket-facing port * * Return: connection pointer, if found, -ENOENT otherwise */ static struct tcp_tap_conn *tcp_hash_lookup(struct ctx *c, int af, void *addr, in_port_t tap_port, in_port_t sock_port) { int b = tcp_hash(c, af, addr, tap_port, sock_port); struct tcp_tap_conn *conn; for (conn = tt_hash[b]; conn; conn = conn->next) { if (tcp_hash_match(conn, af, addr, tap_port, sock_port)) return conn; } return NULL; } /** * tcp_tap_epoll_mask() - Set new epoll event mask given a connection * @c: Execution context * @conn: Connection pointer * @events: New epoll event bitmap */ static void tcp_tap_epoll_mask(struct ctx *c, struct tcp_tap_conn *conn, uint32_t events) { union epoll_ref ref = { .proto = IPPROTO_TCP, .s = conn->sock, .tcp.index = conn - tt, .tcp.v6 = !IN6_IS_ADDR_V4MAPPED(&conn->a.a6) }; struct epoll_event ev = { .data.u64 = ref.u64, .events = events }; if (conn->events == events) return; conn->events = events; epoll_ctl(c->epollfd, EPOLL_CTL_MOD, conn->sock, &ev); } /** * tcp_table_tap_compact() - Perform compaction on tap connection table * @c: Execution context * @hole: Pointer to recently closed connection */ static void tcp_table_tap_compact(struct ctx *c, struct tcp_tap_conn *hole) { struct tcp_tap_conn *from, *to; uint32_t events; if ((hole - tt) == --c->tcp.tap_conn_count) { debug("TCP: hash table compaction: index %i (%p) was max index", hole - tt, hole); return; } from = &tt[c->tcp.tap_conn_count]; memcpy(hole, from, sizeof(*hole)); from->state = CLOSED; to = hole; tcp_hash_update(from, to); events = hole->events; hole->events = UINT_MAX; tcp_tap_epoll_mask(c, hole, events); debug("TCP: hash table compaction: old index %i, new index %i, " "sock %i, from: %p, to: %p", from - tt, to - tt, from->sock, from, to); } /** * tcp_tap_destroy() - Close tap connection, drop from hash table and epoll * @c: Execution context * @conn: Connection pointer */ static void tcp_tap_destroy(struct ctx *c, struct tcp_tap_conn *conn) { if (conn->state == CLOSED) return; epoll_ctl(c->epollfd, EPOLL_CTL_DEL, conn->sock, NULL); tcp_tap_state(conn, CLOSED); close(conn->sock); /* Removal from hash table and connection table compaction deferred to * timer. */ } static void tcp_rst(struct ctx *c, struct tcp_tap_conn *conn); /** * tcp_send_to_tap() - Send segment to tap, with options and values from socket * @c: Execution context * @conn: Connection pointer * @flags: TCP flags to set * @now: Current timestamp, can be NULL * * Return: negative error code on connection reset, 0 otherwise */ static int tcp_send_to_tap(struct ctx *c, struct tcp_tap_conn *conn, int flags, struct timespec *now) { char buf[sizeof(struct tcphdr) + OPT_MSS_LEN + OPT_WS_LEN + 1] = { 0 }; uint32_t prev_ack_to_tap = conn->seq_ack_to_tap; struct tcp_info info = { 0 }; socklen_t sl = sizeof(info); struct tcphdr *th; char *data; if (SEQ_GE(conn->seq_ack_to_tap, conn->seq_from_tap) && !flags && conn->wnd_to_tap) return 0; if (getsockopt(conn->sock, SOL_TCP, TCP_INFO, &info, &sl)) { tcp_rst(c, conn); return -ECONNRESET; } th = (struct tcphdr *)buf; data = (char *)(th + 1); th->doff = sizeof(*th) / 4; if (flags & SYN) { /* Options: MSS, NOP and window scale if allowed (4-8 bytes) */ *data++ = OPT_MSS; *data++ = OPT_MSS_LEN; *(uint16_t *)data = htons(info.tcpi_snd_mss); data += OPT_MSS_LEN - 2; th->doff += OPT_MSS_LEN / 4; if (!c->tcp.kernel_snd_wnd && info.tcpi_snd_wnd) c->tcp.kernel_snd_wnd = 1; conn->ws = MIN(MAX_WS, info.tcpi_snd_wscale); *data++ = OPT_NOP; *data++ = OPT_WS; *data++ = OPT_WS_LEN; *data++ = conn->ws; th->doff += (1 + OPT_WS_LEN) / 4; /* RFC 793, 3.1: "[...] and the first data octet is ISN+1." */ th->seq = htonl(conn->seq_to_tap++); th->ack = !!(flags & ACK); } else { th->ack = 1; th->seq = htonl(conn->seq_to_tap); } if (conn->state > ESTABLISHED || (flags & (DUP_ACK | FORCE_ACK))) { conn->seq_ack_to_tap = conn->seq_from_tap; } else { conn->seq_ack_to_tap = info.tcpi_bytes_acked + conn->seq_init_from_tap; if (SEQ_LT(conn->seq_ack_to_tap, prev_ack_to_tap)) conn->seq_ack_to_tap = prev_ack_to_tap; } if (!flags && conn->seq_ack_to_tap == prev_ack_to_tap && c->tcp.kernel_snd_wnd && conn->wnd_to_tap == info.tcpi_snd_wnd) return 0; th->ack_seq = htonl(conn->seq_ack_to_tap); th->rst = !!(flags & RST); th->syn = !!(flags & SYN); th->fin = !!(flags & FIN); th->source = htons(conn->sock_port); th->dest = htons(conn->tap_port); if (th->syn) { /* First value sent by receiver is not scaled */ th->window = htons(conn->wnd_to_tap = WINDOW_DEFAULT); } else { if (c->tcp.kernel_snd_wnd) { conn->wnd_to_tap = MIN(info.tcpi_snd_wnd, conn->snd_buf); } else { conn->wnd_to_tap = conn->snd_buf; } conn->wnd_to_tap = MIN(conn->wnd_to_tap, MAX_WINDOW); th->window = htons(MIN(conn->wnd_to_tap >> conn->ws, USHRT_MAX)); } th->urg_ptr = 0; th->check = 0; if (th->ack && now) conn->ts_ack_to_tap = *now; tap_ip_send(c, &conn->a.a6, IPPROTO_TCP, buf, th->doff * 4, conn->seq_init_to_tap); if (flags & DUP_ACK) { tap_ip_send(c, &conn->a.a6, IPPROTO_TCP, buf, th->doff * 4, conn->seq_init_to_tap); } if (th->fin) { conn->tap_data_noack = *now; conn->seq_to_tap++; } return 0; } /** * tcp_rst() - Reset a tap connection: send RST segment to tap, close socket * @c: Execution context * @conn: Connection pointer */ static void tcp_rst(struct ctx *c, struct tcp_tap_conn *conn) { if (conn->state == CLOSED) return; tcp_send_to_tap(c, conn, RST, NULL); tcp_tap_destroy(c, conn); } /** * tcp_clamp_window() - Set window and scaling from option, clamp on socket * @conn: Connection pointer * @th: TCP header, from tap, can be NULL if window is passed * @len: Buffer length, at L4, can be 0 if no header is passed * @window: Window value, host order, unscaled, if no header is passed * @init: Set if this is the very first segment from tap */ static void tcp_clamp_window(struct tcp_tap_conn *conn, struct tcphdr *th, int len, unsigned int window, int init) { if (init) { int ws = tcp_opt_get(th, len, OPT_WS, NULL, NULL); conn->ws_tap = ws; /* RFC 7323, 2.2: first value is not scaled. Also, don't clamp * yet, to avoid getting a zero scale just because we set a * small window now. */ conn->wnd_from_tap = ntohs(th->window); conn->window_clamped = 0; } else { if (th) window = ntohs(th->window) << conn->ws_tap; else window <<= conn->ws_tap; window = MIN(MAX_WINDOW, window); if (conn->window_clamped) { if (conn->wnd_from_tap == window) return; /* Discard +/- 1% updates to spare some syscalls. */ if ((window > conn->wnd_from_tap && window * 99 / 100 < conn->wnd_from_tap) || (window < conn->wnd_from_tap && window * 101 / 100 > conn->wnd_from_tap)) { conn->wnd_from_tap = window; return; } } conn->wnd_from_tap = window; if (window < 256) window = 256; setsockopt(conn->sock, SOL_TCP, TCP_WINDOW_CLAMP, &window, sizeof(window)); conn->window_clamped = 1; } } /** * tcp_seq_init() - Calculate initial sequence number according to RFC 6528 * @c: Execution context * @af: Address family, AF_INET or AF_INET6 * @addr: Remote address, pointer to sin_addr or sin6_addr * @dstport: Destination port, connection-wise, network order * @srcport: Source port, connection-wise, network order * @now: Current timestamp * * Return: initial TCP sequence */ static uint32_t tcp_seq_init(struct ctx *c, int af, void *addr, in_port_t dstport, in_port_t srcport, struct timespec *now) { uint32_t ns, seq = 0; if (af == AF_INET) { struct { struct in_addr src; in_port_t srcport; struct in_addr dst; in_port_t dstport; } __attribute__((__packed__)) in = { .src = *(struct in_addr *)addr, .srcport = srcport, .dst = { c->addr4 }, .dstport = dstport, }; seq = siphash_12b((uint8_t *)&in, c->tcp.hash_secret); } else if (af == AF_INET6) { struct { struct in6_addr src; in_port_t srcport; struct in6_addr dst; in_port_t dstport; } __attribute__((__packed__)) in = { .src = *(struct in6_addr *)addr, .srcport = srcport, .dst = c->addr6, .dstport = dstport, }; seq = siphash_36b((uint8_t *)&in, c->tcp.hash_secret); } ns = now->tv_sec * 1E9; ns += now->tv_nsec >> 5; /* 32ns ticks, overflows 32 bits every 137s */ return seq + ns; } /** * tcp_conn_from_tap() - Handle connection request (SYN segment) from tap * @c: Execution context * @af: Address family, AF_INET or AF_INET6 * @addr: Remote address, pointer to sin_addr or sin6_addr * @th: TCP header from tap * @len: Packet length at L4 * @now: Current timestamp */ static void tcp_conn_from_tap(struct ctx *c, int af, void *addr, struct tcphdr *th, size_t len, struct timespec *now) { struct sockaddr_in addr4 = { .sin_family = AF_INET, .sin_port = th->dest, .sin_addr = *(struct in_addr *)addr, }; struct sockaddr_in6 addr6 = { .sin6_family = AF_INET6, .sin6_port = th->dest, .sin6_addr = *(struct in6_addr *)addr, }; union epoll_ref ref = { .proto = IPPROTO_TCP }; const struct sockaddr *sa; struct tcp_tap_conn *conn; int i, s, *sock_pool_p; struct epoll_event ev; socklen_t sl; if (c->tcp.tap_conn_count >= MAX_TAP_CONNS) return; for (i = 0; i < TCP_SOCK_POOL_SIZE; i++) { if (af == AF_INET6) sock_pool_p = &init_sock_pool6[i]; else sock_pool_p = &init_sock_pool4[i]; if ((ref.s = s = *sock_pool_p) > 0) { *sock_pool_p = -1; break; } } if (s < 0) ref.s = s = socket(af, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP); if (s < 0) return; tcp_sock_set_bufsize(s); if (af == AF_INET && addr4.sin_addr.s_addr == c->gw4) addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK); else if (af == AF_INET6 && !memcmp(addr, &c->gw6, sizeof(c->gw6))) addr6.sin6_addr = in6addr_loopback; if (af == AF_INET6 && IN6_IS_ADDR_LINKLOCAL(&addr6.sin6_addr)) { struct sockaddr_in6 addr6_ll = { .sin6_family = AF_INET6, .sin6_addr = c->addr6_ll, .sin6_scope_id = if_nametoindex(c->ifn), }; bind(s, (struct sockaddr *)&addr6_ll, sizeof(addr6_ll)); } conn = &tt[c->tcp.tap_conn_count++]; conn->sock = s; conn->events = 0; conn->wnd_to_tap = WINDOW_DEFAULT; conn->mss_guest = tcp_opt_get(th, len, OPT_MSS, NULL, NULL); if (conn->mss_guest < 0) conn->mss_guest = MSS_DEFAULT; if (c->mode == MODE_PASST) { /* Don't upset qemu */ conn->mss_guest = MIN(USHRT_MAX - sizeof(uint32_t) - sizeof(struct ethhdr) - sizeof(struct ipv6hdr) - sizeof(struct tcphdr), conn->mss_guest); } sl = sizeof(conn->mss_guest); setsockopt(s, SOL_TCP, TCP_MAXSEG, &conn->mss_guest, sl); tcp_clamp_window(conn, th, len, 0, 1); if (af == AF_INET) { sa = (struct sockaddr *)&addr4; sl = sizeof(addr4); memset(&conn->a.a4.zero, 0, sizeof(conn->a.a4.zero)); memset(&conn->a.a4.one, 0xff, sizeof(conn->a.a4.one)); memcpy(&conn->a.a4.a, addr, sizeof(conn->a.a4.a)); } else { sa = (struct sockaddr *)&addr6; sl = sizeof(addr6); memcpy(&conn->a.a6, addr, sizeof(conn->a.a6)); } conn->sock_port = ntohs(th->dest); conn->tap_port = ntohs(th->source); conn->ts_sock_act = conn->ts_tap_act = *now; conn->ts_ack_to_tap = conn->ts_ack_from_tap = *now; conn->seq_init_from_tap = ntohl(th->seq); conn->seq_from_tap = conn->seq_init_from_tap + 1; conn->seq_ack_to_tap = conn->seq_from_tap; conn->seq_to_tap = tcp_seq_init(c, af, addr, th->dest, th->source, now); conn->seq_init_to_tap = conn->seq_to_tap; conn->seq_ack_from_tap = conn->seq_to_tap + 1; tcp_hash_insert(c, conn, af, addr); if (connect(s, sa, sl)) { tcp_tap_state(conn, TAP_SYN_SENT); if (errno != EINPROGRESS) { tcp_rst(c, conn); return; } ev.events = EPOLLOUT | EPOLLRDHUP; } else { tcp_tap_state(conn, TAP_SYN_RCVD); if (tcp_send_to_tap(c, conn, SYN | ACK, now)) return; ev.events = EPOLLIN | EPOLLRDHUP; } sl = sizeof(conn->snd_buf); if (getsockopt(s, SOL_SOCKET, SO_SNDBUF, &conn->snd_buf, &sl)) conn->snd_buf = WINDOW_DEFAULT; else conn->snd_buf /= 2; conn->events = ev.events; ref.tcp.index = conn - tt; ev.data.u64 = ref.u64; epoll_ctl(c->epollfd, EPOLL_CTL_ADD, s, &ev); } /** * tcp_table_splice_compact - Compact spliced connection table * @c: Execution context * @hole: Pointer to recently closed connection */ static void tcp_table_splice_compact(struct ctx *c, struct tcp_splice_conn *hole) { union epoll_ref ref_from = { .proto = IPPROTO_TCP, .tcp.splice = 1, .tcp.index = hole - ts }; union epoll_ref ref_to = { .proto = IPPROTO_TCP, .tcp.splice = 1, .tcp.index = hole - ts }; struct tcp_splice_conn *move; struct epoll_event ev_from; struct epoll_event ev_to; hole->from_fin_sent = hole->to_fin_sent = 0; hole->from_read = hole->from_written = 0; hole->to_read = hole->to_written = 0; bitmap_clear(splice_rcvlowat_set[0], hole - ts); bitmap_clear(splice_rcvlowat_set[1], hole - ts); bitmap_clear(splice_rcvlowat_act[0], hole - ts); bitmap_clear(splice_rcvlowat_act[1], hole - ts); if ((hole - ts) == --c->tcp.splice_conn_count) return; move = &ts[c->tcp.splice_conn_count]; if (move->state == CLOSED) return; memcpy(hole, move, sizeof(*hole)); move->state = CLOSED; move = hole; ref_from.s = move->from; ref_from.tcp.v6 = move->v6; ref_to.s = move->to; ref_to.tcp.v6 = move->v6; if (move->state == SPLICE_ACCEPTED) { ev_from.events = ev_to.events = 0; } else if (move->state == SPLICE_CONNECT) { ev_from.events = 0; ev_to.events = EPOLLOUT; } else { ev_from.events = EPOLLIN | EPOLLOUT | EPOLLRDHUP; ev_to.events = EPOLLIN | EPOLLOUT | EPOLLRDHUP; } ev_from.data.u64 = ref_from.u64; ev_to.data.u64 = ref_to.u64; epoll_ctl(c->epollfd, EPOLL_CTL_MOD, move->from, &ev_from); epoll_ctl(c->epollfd, EPOLL_CTL_MOD, move->to, &ev_to); } /** * tcp_splice_destroy() - Close spliced connection and pipes, drop from epoll * @c: Execution context * @conn: Connection pointer */ static void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn) { int epoll_del_done = 0; switch (conn->state) { case CLOSED: epoll_del_done = 1; /* Falls through */ case SPLICE_FIN_BOTH: case SPLICE_FIN_FROM: case SPLICE_FIN_TO: case SPLICE_ESTABLISHED: /* Flushing might need to block: don't recycle them. */ if (conn->pipe_from_to[0] != -1) { close(conn->pipe_from_to[0]); conn->pipe_from_to[0] = -1; close(conn->pipe_from_to[1]); conn->pipe_from_to[1] = -1; } if (conn->pipe_to_from[0] != -1) { close(conn->pipe_to_from[0]); conn->pipe_to_from[0] = -1; close(conn->pipe_to_from[1]); conn->pipe_to_from[1] = -1; } /* Falls through */ case SPLICE_CONNECT: if (!epoll_del_done) { epoll_ctl(c->epollfd, EPOLL_CTL_DEL, conn->from, NULL); epoll_ctl(c->epollfd, EPOLL_CTL_DEL, conn->to, NULL); } close(conn->to); /* Falls through */ case SPLICE_ACCEPTED: close(conn->from); tcp_splice_state(conn, CLOSED); tcp_table_splice_compact(c, conn); break; default: return; } } /** * tcp_sock_consume() - Consume (discard) data from buffer, update ACK sequence * @conn: Connection pointer * @ack_seq: ACK sequence, host order */ static void tcp_sock_consume(struct tcp_tap_conn *conn, uint32_t ack_seq) { /* Simply ignore out-of-order ACKs: we already consumed the data we * needed from the buffer, and we won't rewind back to a lower ACK * sequence. */ if (SEQ_LE(ack_seq, conn->seq_ack_from_tap)) return; recv(conn->sock, NULL, ack_seq - conn->seq_ack_from_tap, MSG_DONTWAIT | MSG_TRUNC); conn->seq_ack_from_tap = ack_seq; } /** * tcp_data_from_sock() - Handle new data from socket, queue to tap, in window * @c: Execution context * @conn: Connection pointer * @now: Current timestamp * * Return: negative on connection reset, 0 otherwise */ static int tcp_data_from_sock(struct ctx *c, struct tcp_tap_conn *conn, struct timespec *now) { int *buf_mss, *buf_mss_nr_set, *buf_mss_tap, *buf_mss_tap_nr_set; int mss_tap, fill_bufs, send_bufs = 0, last_len, iov_rem = 0; int send, len, plen, v4 = IN6_IS_ADDR_V4MAPPED(&conn->a.a6); uint32_t seq_to_tap = conn->seq_to_tap; socklen_t sl = sizeof(struct tcp_info); int s = conn->sock, i, ret = 0; struct iovec *iov, *iov_tap; uint32_t already_sent; struct tcp_info info; struct mmsghdr *mh; already_sent = conn->seq_to_tap - conn->seq_ack_from_tap; if (SEQ_LT(already_sent, 0)) { /* RFC 761, section 2.1. */ seq_to_tap = conn->seq_to_tap = conn->seq_ack_from_tap; already_sent = 0; } if (!conn->wnd_from_tap || already_sent >= conn->wnd_from_tap) { tcp_tap_epoll_mask(c, conn, conn->events | EPOLLET); return 0; } fill_bufs = DIV_ROUND_UP(conn->wnd_from_tap - already_sent, conn->mss_guest); if (fill_bufs > TCP_TAP_FRAMES) { fill_bufs = TCP_TAP_FRAMES; iov_rem = 0; } else { iov_rem = (conn->wnd_from_tap - already_sent) % conn->mss_guest; } /* Adjust iovec length for recvmsg() based on what was set last time. */ if (v4) { iov = tcp4_l2_iov_sock + 1; buf_mss = &tcp4_l2_buf_mss; buf_mss_nr_set = &tcp4_l2_buf_mss_nr_set; } else { iov = tcp6_l2_iov_sock + 1; buf_mss = &tcp6_l2_buf_mss; buf_mss_nr_set = &tcp6_l2_buf_mss_nr_set; } if (*buf_mss != conn->mss_guest) *buf_mss_nr_set = 0; for (i = *buf_mss_nr_set; i < fill_bufs; i++) iov[i].iov_len = conn->mss_guest; *buf_mss = conn->mss_guest; *buf_mss_nr_set = fill_bufs - 1; /* First buffer is to discard data, last one may be partially filled. */ iov[-1].iov_len = already_sent; if (iov_rem) iov[fill_bufs - 1].iov_len = iov_rem; if (v4) tcp4_l2_mh_sock.msg_iovlen = fill_bufs + 1; else tcp6_l2_mh_sock.msg_iovlen = fill_bufs + 1; /* Don't dequeue until acknowledged by guest. */ recvmsg: len = recvmsg(s, v4 ? &tcp4_l2_mh_sock : &tcp6_l2_mh_sock, MSG_PEEK); if (len < 0) { if (errno == EINTR) goto recvmsg; goto err; } if (!len) goto zero_len; send = len - already_sent; if (send <= 0) { tcp_tap_epoll_mask(c, conn, conn->events | EPOLLET); goto out; } tcp_tap_epoll_mask(c, conn, conn->events & ~EPOLLET); send_bufs = DIV_ROUND_UP(send, conn->mss_guest); last_len = send - (send_bufs - 1) * conn->mss_guest; /* Adjust iovec length for sending based on what was set last time. */ if (v4) { mss_tap = conn->mss_guest + offsetof(struct tcp4_l2_buf_t, data) - offsetof(struct tcp4_l2_buf_t, vnet_len); iov_tap = tcp4_l2_iov_tap; buf_mss_tap = &tcp4_l2_buf_mss_tap; buf_mss_tap_nr_set = &tcp4_l2_buf_mss_tap_nr_set; } else { mss_tap = conn->mss_guest + offsetof(struct tcp6_l2_buf_t, data) - offsetof(struct tcp6_l2_buf_t, vnet_len); iov_tap = tcp6_l2_iov_tap; buf_mss_tap = &tcp6_l2_buf_mss_tap; buf_mss_tap_nr_set = &tcp6_l2_buf_mss_tap_nr_set; } if (*buf_mss_tap != mss_tap) *buf_mss_tap_nr_set = 0; for (i = *buf_mss_tap_nr_set; i < send_bufs; i++) iov_tap[i].iov_len = mss_tap; *buf_mss_tap = mss_tap; *buf_mss_tap_nr_set = send_bufs; iov_tap[send_bufs - 1].iov_len = mss_tap - conn->mss_guest + last_len; /* Likely, some new data was acked too. */ if (conn->seq_from_tap != conn->seq_ack_to_tap || !conn->wnd_to_tap) { if (conn->state != ESTABLISHED || getsockopt(s, SOL_TCP, TCP_INFO, &info, &sl)) { conn->seq_ack_to_tap = conn->seq_from_tap; } else { conn->seq_ack_to_tap = info.tcpi_bytes_acked + conn->seq_init_from_tap; if (c->tcp.kernel_snd_wnd) { conn->wnd_to_tap = MIN(info.tcpi_snd_wnd, conn->snd_buf); } else { conn->wnd_to_tap = conn->snd_buf; } conn->wnd_to_tap = MIN(conn->wnd_to_tap, MAX_WINDOW); } } plen = conn->mss_guest; for (i = 0, mh = tcp_l2_mh_tap; i < send_bufs; i++, mh++) { int ip_len; if (i == send_bufs - 1) plen = last_len; if (v4) { struct tcp4_l2_buf_t *b = &tcp4_l2_buf[i]; ip_len = plen + sizeof(struct iphdr) + sizeof(struct tcphdr); b->iph.tot_len = htons(ip_len); b->iph.saddr = conn->a.a4.a.s_addr; b->iph.daddr = c->addr4_seen; if (!i || i == send_bufs - 1) tcp_update_check_ip4(b); else b->iph.check = tcp4_l2_buf[0].iph.check; b->th.source = htons(conn->sock_port); b->th.dest = htons(conn->tap_port); b->th.seq = htonl(seq_to_tap); b->th.ack_seq = htonl(conn->seq_ack_to_tap); b->th.window = htons(MIN(conn->wnd_to_tap >> conn->ws, USHRT_MAX)); tcp_update_check_tcp4(b); if (c->mode == MODE_PASST) { b->vnet_len = htonl(sizeof(struct ethhdr) + ip_len); mh->msg_hdr.msg_iov = &tcp4_l2_iov_tap[i]; seq_to_tap += plen; continue; } ip_len += sizeof(struct ethhdr); pcap((char *)&b->eh, ip_len); ret = write(c->fd_tap, &b->eh, ip_len); } else { struct tcp6_l2_buf_t *b = &tcp6_l2_buf[i]; uint32_t flow = conn->seq_init_to_tap; ip_len = plen + sizeof(struct ipv6hdr) + sizeof(struct tcphdr); b->ip6h.payload_len = htons(plen + sizeof(struct tcphdr)); b->ip6h.saddr = conn->a.a6; if (IN6_IS_ADDR_LINKLOCAL(&b->ip6h.saddr)) b->ip6h.daddr = c->addr6_ll_seen; else b->ip6h.daddr = c->addr6_seen; b->th.source = htons(conn->sock_port); b->th.dest = htons(conn->tap_port); b->th.seq = htonl(seq_to_tap); b->th.ack_seq = htonl(conn->seq_ack_to_tap); b->th.window = htons(MIN(conn->wnd_to_tap >> conn->ws, USHRT_MAX)); memset(b->ip6h.flow_lbl, 0, 3); tcp_update_check_tcp6(b); b->ip6h.flow_lbl[0] = (flow >> 16) & 0xf; b->ip6h.flow_lbl[1] = (flow >> 8) & 0xff; b->ip6h.flow_lbl[2] = (flow >> 0) & 0xff; if (c->mode == MODE_PASST) { b->vnet_len = htonl(sizeof(struct ethhdr) + ip_len); mh->msg_hdr.msg_iov = &tcp6_l2_iov_tap[i]; seq_to_tap += plen; continue; } ip_len += sizeof(struct ethhdr); pcap((char *)&b->eh, ip_len); ret = write(c->fd_tap, &b->eh, ip_len); } if (ret < ip_len) { if (ret < 0) { if (errno == EAGAIN || errno == EWOULDBLOCK) return 0; tap_handler(c, EPOLLERR, now); } i--; continue; } conn->seq_to_tap += plen; } if (c->mode == MODE_PASTA) goto out; sendmmsg: ret = sendmmsg(c->fd_tap, tcp_l2_mh_tap, mh - tcp_l2_mh_tap, MSG_NOSIGNAL | MSG_DONTWAIT); if (ret < 0 && errno == EINTR) goto sendmmsg; if (ret <= 0) goto out; conn->tap_data_noack = *now; conn->seq_to_tap += conn->mss_guest * (ret - 1) + last_len; /* sendmmsg() indicates how many messages were sent at least partially. * Kernel commit 3023898b7d4a ("sock: fix sendmmsg for partial sendmsg") * gives us the guarantee that at most one message, namely the last sent * one, might have been sent partially. Check how many bytes of that * message were sent, and re-send any missing bytes with a blocking * sendmsg(), otherwise qemu will fail to parse any subsequent message. */ mh = &tcp_l2_mh_tap[ret - 1]; if (mh->msg_len < mh->msg_hdr.msg_iov->iov_len) { uint8_t **iov_base = (uint8_t **)&mh->msg_hdr.msg_iov->iov_base; int part_sent = mh->msg_len; mh->msg_hdr.msg_iov->iov_len -= part_sent; *iov_base += part_sent; sendmsg(c->fd_tap, &mh->msg_hdr, MSG_NOSIGNAL); mh->msg_hdr.msg_iov->iov_len += part_sent; *iov_base -= part_sent; } conn->ts_ack_to_tap = *now; pcapmm(tcp_l2_mh_tap, ret); goto out; err: if (errno != EAGAIN && errno != EWOULDBLOCK) { tcp_rst(c, conn); ret = -errno; } goto out; zero_len: if (conn->state == ESTABLISHED_SOCK_FIN) { tcp_tap_epoll_mask(c, conn, EPOLLET); tcp_send_to_tap(c, conn, FIN | ACK, now); tcp_tap_state(conn, ESTABLISHED_SOCK_FIN_SENT); } out: if (iov_rem) iov[fill_bufs - 1].iov_len = conn->mss_guest; if (send_bufs) iov_tap[send_bufs - 1].iov_len = mss_tap; return ret; } /** * tcp_data_from_tap() - tap data in ESTABLISHED{,SOCK_FIN}, CLOSE_WAIT states * @c: Execution context * @conn: Connection pointer * @msg: Array of messages from tap * @count: Count of messages * @now: Current timestamp */ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn, struct tap_l4_msg *msg, int count, struct timespec *now) { int i, iov_i, ack = 0, fin = 0, psh = 0, retr = 0, keep = -1; struct msghdr mh = { .msg_iov = tcp_tap_iov }; uint32_t max_ack_seq = conn->seq_ack_from_tap; uint16_t max_ack_seq_wnd = conn->wnd_from_tap; uint32_t seq_from_tap = conn->seq_from_tap; int partial_send = 0; uint16_t len; ssize_t n; for (i = 0, iov_i = 0; i < count; i++) { uint32_t seq, seq_offset, ack_seq; struct tcphdr *th; char *data; size_t off; th = (struct tcphdr *)(pkt_buf + msg[i].pkt_buf_offset); len = msg[i].l4_len; if (len < sizeof(*th)) { tcp_rst(c, conn); return; } off = th->doff * 4; if (off < sizeof(*th) || off > len) { tcp_rst(c, conn); return; } if (th->rst) { tcp_tap_destroy(c, conn); return; } len -= off; data = (char *)th + off; seq = ntohl(th->seq); ack_seq = ntohl(th->ack_seq); if (th->ack) { ack = 1; if (SEQ_GE(ack_seq, conn->seq_ack_from_tap) && SEQ_GE(ack_seq, max_ack_seq)) { /* Fast re-transmit */ retr = !len && !th->fin && ack_seq == max_ack_seq && max_ack_seq_wnd == ntohs(th->window); max_ack_seq_wnd = ntohs(th->window); max_ack_seq = ack_seq; } } if (th->fin) fin = 1; if (th->psh) psh = 1; if (!len) continue; seq_offset = seq_from_tap - seq; /* Use data from this buffer only in these two cases: * * , seq_from_tap , seq_from_tap * |--------| <-- len |--------| <-- len * '----' <-- offset ' <-- offset * ^ seq ^ seq * (offset >= 0, seq + len > seq_from_tap) * * discard in these two cases: * , seq_from_tap , seq_from_tap * |--------| <-- len |--------| <-- len * '--------' <-- offset '-----| <- offset * ^ seq ^ seq * (offset >= 0, seq + len <= seq_from_tap) * * keep, look for another buffer, then go back, in this case: * , seq_from_tap * |--------| <-- len * '===' <-- offset * ^ seq * (offset < 0) */ if (SEQ_GE(seq_offset, 0) && SEQ_LE(seq + len, seq_from_tap)) { /* Force sending ACK, sender might have lost one */ psh = 1; continue; } if (SEQ_LT(seq_offset, 0)) { if (keep == -1) keep = i; continue; } tcp_tap_iov[iov_i].iov_base = data + seq_offset; tcp_tap_iov[iov_i].iov_len = len - seq_offset; seq_from_tap += tcp_tap_iov[iov_i].iov_len; iov_i++; if (keep == i) keep = -1; if (keep != -1) i = keep - 1; } tcp_clamp_window(conn, NULL, 0, max_ack_seq_wnd, 0); if (ack) { conn->ts_ack_from_tap = *now; conn->tap_data_noack = ((struct timespec) { 0, 0 }); tcp_sock_consume(conn, max_ack_seq); } if (retr) { conn->seq_ack_from_tap = max_ack_seq; conn->seq_to_tap = max_ack_seq; tcp_data_from_sock(c, conn, now); } if (!iov_i) goto out; mh.msg_iovlen = iov_i; eintr: n = sendmsg(conn->sock, &mh, MSG_DONTWAIT | MSG_NOSIGNAL); if (n < 0) { if (errno == EPIPE) { /* Here's the wrap, said the tap. * In my pocket, said the socket. * Then swiftly looked away and left. */ conn->seq_from_tap = seq_from_tap; tcp_send_to_tap(c, conn, FORCE_ACK, now); } if (errno == EINTR) goto eintr; if (errno == EAGAIN || errno == EWOULDBLOCK) { tcp_send_to_tap(c, conn, UPDATE_WINDOW, now); return; } tcp_rst(c, conn); return; } if (n < (seq_from_tap - conn->seq_from_tap)) { partial_send = 1; tcp_send_to_tap(c, conn, UPDATE_WINDOW, now); } conn->seq_from_tap += n; out: if (keep != -1) { if (conn->seq_dup_ack != conn->seq_from_tap) { conn->seq_dup_ack = conn->seq_from_tap; tcp_send_to_tap(c, conn, DUP_ACK, now); } return; } if (ack) { if (conn->state == ESTABLISHED_SOCK_FIN_SENT && conn->seq_ack_from_tap == conn->seq_to_tap) tcp_tap_state(conn, CLOSE_WAIT); } if (fin && !partial_send) { conn->seq_from_tap++; if (conn->state == ESTABLISHED) { shutdown(conn->sock, SHUT_WR); tcp_tap_state(conn, FIN_WAIT_1); tcp_send_to_tap(c, conn, ACK, now); } else if (conn->state == CLOSE_WAIT) { shutdown(conn->sock, SHUT_WR); tcp_tap_state(conn, LAST_ACK); tcp_send_to_tap(c, conn, ACK, now); } } else { int ack_to_tap = timespec_diff_ms(now, &conn->ts_ack_to_tap); int ack_offset = conn->seq_from_tap - conn->seq_ack_to_tap; if (c->mode == MODE_PASTA || psh || SEQ_GE(ack_offset, conn->wnd_to_tap / 2) || ack_to_tap > ACK_INTERVAL) { tcp_send_to_tap(c, conn, psh ? FORCE_ACK : 0, now); } } } /** * tcp_tap_handler() - Handle packets from tap and state transitions * @c: Execution context * @af: Address family, AF_INET or AF_INET6 * @addr: Destination address * @msg: Input messages * @count: Message count * @now: Current timestamp * * Return: count of consumed packets */ int tcp_tap_handler(struct ctx *c, int af, void *addr, struct tap_l4_msg *msg, int count, struct timespec *now) { struct tcphdr *th = (struct tcphdr *)(pkt_buf + msg[0].pkt_buf_offset); uint16_t len = msg[0].l4_len; struct tcp_tap_conn *conn; conn = tcp_hash_lookup(c, af, addr, htons(th->source), htons(th->dest)); if (!conn) { if (th->syn && !th->ack) tcp_conn_from_tap(c, af, addr, th, len, now); return 1; } if (th->rst) { tcp_tap_destroy(c, conn); return count; } conn->ts_tap_act = *now; switch (conn->state) { case SOCK_SYN_SENT: if (!th->syn || !th->ack) { tcp_rst(c, conn); return count; } tcp_clamp_window(conn, th, len, 0, 1); conn->mss_guest = tcp_opt_get(th, len, OPT_MSS, NULL, NULL); if (conn->mss_guest < 0) conn->mss_guest = MSS_DEFAULT; if (c->mode == MODE_PASST) { /* Don't upset qemu */ conn->mss_guest = MIN(USHRT_MAX - sizeof(uint32_t) - sizeof(struct ethhdr) - sizeof(struct ipv6hdr) - sizeof(struct tcphdr), conn->mss_guest); } /* info.tcpi_bytes_acked already includes one byte for SYN, but * not for incoming connections. */ conn->seq_init_from_tap = ntohl(th->seq) + 1; conn->seq_from_tap = conn->seq_init_from_tap; conn->seq_ack_to_tap = conn->seq_from_tap; tcp_tap_state(conn, ESTABLISHED); /* The client might have sent data already, which we didn't * dequeue waiting for SYN,ACK from tap -- check now. */ tcp_data_from_sock(c, conn, now); tcp_send_to_tap(c, conn, 0, now); tcp_tap_epoll_mask(c, conn, EPOLLIN | EPOLLRDHUP); break; case TAP_SYN_RCVD: if (th->fin) { conn->seq_from_tap++; shutdown(conn->sock, SHUT_WR); tcp_send_to_tap(c, conn, ACK, now); tcp_tap_state(conn, FIN_WAIT_1); break; } if (!th->ack) { tcp_rst(c, conn); return count; } tcp_clamp_window(conn, th, len, 0, 0); tcp_tap_state(conn, ESTABLISHED); if (count == 1) break; /* Falls through */ case ESTABLISHED: case ESTABLISHED_SOCK_FIN: case ESTABLISHED_SOCK_FIN_SENT: tcp_tap_epoll_mask(c, conn, conn->events & ~EPOLLET); tcp_data_from_tap(c, conn, msg, count, now); return count; case CLOSE_WAIT: case FIN_WAIT_1_SOCK_FIN: case FIN_WAIT_1: if (th->ack) { conn->tap_data_noack = ((struct timespec) { 0, 0 }); conn->ts_ack_from_tap = *now; } tcp_sock_consume(conn, ntohl(th->ack_seq)); if (conn->state == FIN_WAIT_1_SOCK_FIN && conn->seq_ack_from_tap == conn->seq_to_tap) { tcp_tap_destroy(c, conn); return count; } tcp_tap_epoll_mask(c, conn, conn->events & ~EPOLLET); return count; case TAP_SYN_SENT: case LAST_ACK: case SPLICE_ACCEPTED: case SPLICE_CONNECT: case SPLICE_ESTABLISHED: case SPLICE_FIN_FROM: case SPLICE_FIN_TO: case SPLICE_FIN_BOTH: case CLOSED: /* ;) */ break; } return 1; } /** * tcp_connect_finish() - Handle completion of connect() from EPOLLOUT event * @c: Execution context * @s: File descriptor number for socket * @now: Current timestamp */ static void tcp_connect_finish(struct ctx *c, struct tcp_tap_conn *conn, struct timespec *now) { socklen_t sl; int so; sl = sizeof(so); if (getsockopt(conn->sock, SOL_SOCKET, SO_ERROR, &so, &sl) || so) { tcp_rst(c, conn); return; } if (tcp_send_to_tap(c, conn, SYN | ACK, now)) return; /* Drop EPOLLOUT, only used to wait for connect() to complete */ tcp_tap_epoll_mask(c, conn, EPOLLIN | EPOLLRDHUP); tcp_tap_state(conn, TAP_SYN_RCVD); } /** * tcp_splice_connect_finish() - Completion of connect() or call on success * @c: Execution context * @conn: Connection pointer * @v6: Set on IPv6 connection */ static void tcp_splice_connect_finish(struct ctx *c, struct tcp_splice_conn *conn, int v6) { union epoll_ref ref_from = { .proto = IPPROTO_TCP, .s = conn->from, .tcp = { .splice = 1, .v6 = v6, .index = conn - ts } }; union epoll_ref ref_to = { .proto = IPPROTO_TCP, .s = conn->to, .tcp = { .splice = 1, .v6 = v6, .index = conn - ts } }; struct epoll_event ev_from, ev_to; int i; conn->pipe_from_to[0] = conn->pipe_to_from[0] = -1; conn->pipe_from_to[1] = conn->pipe_to_from[1] = -1; for (i = 0; i < TCP_SPLICE_PIPE_POOL_SIZE; i++) { if (splice_pipe_pool[i][0][0] > 0) { SWAP(conn->pipe_from_to[0], splice_pipe_pool[i][0][0]); SWAP(conn->pipe_from_to[1], splice_pipe_pool[i][0][1]); SWAP(conn->pipe_to_from[0], splice_pipe_pool[i][1][0]); SWAP(conn->pipe_to_from[1], splice_pipe_pool[i][1][1]); break; } } if (conn->pipe_from_to[0] <= 0) { if (pipe2(conn->pipe_to_from, O_NONBLOCK) || pipe2(conn->pipe_from_to, O_NONBLOCK)) { tcp_splice_destroy(c, conn); return; } fcntl(conn->pipe_from_to[0], F_SETPIPE_SZ, c->tcp.pipe_size); fcntl(conn->pipe_to_from[0], F_SETPIPE_SZ, c->tcp.pipe_size); } if (conn->state == SPLICE_CONNECT) { tcp_splice_state(conn, SPLICE_ESTABLISHED); ev_from.events = ev_to.events = EPOLLIN | EPOLLRDHUP; ev_from.data.u64 = ref_from.u64; ev_to.data.u64 = ref_to.u64; epoll_ctl(c->epollfd, EPOLL_CTL_ADD, conn->from, &ev_from); epoll_ctl(c->epollfd, EPOLL_CTL_MOD, conn->to, &ev_to); } } /** * tcp_splice_connect() - Create and connect socket for new spliced connection * @c: Execution context * @conn: Connection pointer * @v6: Set on IPv6 connection * @port: Destination port, host order * * Return: 0 for connect() succeeded or in progress, negative value on error */ static int tcp_splice_connect(struct ctx *c, struct tcp_splice_conn *conn, int s, int v6, in_port_t port) { int sock_conn = (s > 0) ? s : socket(v6 ? AF_INET6 : AF_INET, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP); union epoll_ref ref_accept = { .proto = IPPROTO_TCP, .s = conn->from, .tcp = { .splice = 1, .v6 = v6, .index = conn - ts } }; union epoll_ref ref_conn = { .proto = IPPROTO_TCP, .s = sock_conn, .tcp = { .splice = 1, .v6 = v6, .index = conn - ts } }; struct epoll_event ev_accept = { .data.u64 = ref_accept.u64 }; struct epoll_event ev_conn = { .data.u64 = ref_conn.u64 }; struct sockaddr_in6 addr6 = { .sin6_family = AF_INET6, .sin6_port = htons(port), .sin6_addr = IN6ADDR_LOOPBACK_INIT, }; struct sockaddr_in addr4 = { .sin_family = AF_INET, .sin_port = htons(port), .sin_addr = { .s_addr = htonl(INADDR_LOOPBACK) }, }; const struct sockaddr *sa; socklen_t sl; int ret; conn->to = sock_conn; if (s <= 0) tcp_sock_set_bufsize(sock_conn); if (v6) { sa = (struct sockaddr *)&addr6; sl = sizeof(addr6); } else { sa = (struct sockaddr *)&addr4; sl = sizeof(addr4); } if (connect(conn->to, sa, sl)) { if (errno != EINPROGRESS) { ret = -errno; close(sock_conn); return ret; } tcp_splice_state(conn, SPLICE_CONNECT); ev_conn.events = EPOLLOUT; } else { tcp_splice_state(conn, SPLICE_ESTABLISHED); tcp_splice_connect_finish(c, conn, v6); ev_accept.events = EPOLLIN | EPOLLOUT | EPOLLRDHUP; ev_conn.events = EPOLLIN | EPOLLOUT | EPOLLRDHUP; epoll_ctl(c->epollfd, EPOLL_CTL_ADD, conn->from, &ev_accept); } epoll_ctl(c->epollfd, EPOLL_CTL_ADD, conn->to, &ev_conn); return 0; } /** * struct tcp_splice_connect_ns_arg - Arguments for tcp_splice_connect_ns() * @c: Execution context * @conn: Accepted inbound connection * @v6: Set for inbound IPv6 connection * @port: Destination port, host order * @ret: Return value of tcp_splice_connect_ns() */ struct tcp_splice_connect_ns_arg { struct ctx *c; struct tcp_splice_conn *conn; int v6; in_port_t port; int ret; }; /** * tcp_splice_connect_ns() - Enter namespace and call tcp_splice_connect() * @arg: See struct tcp_splice_connect_ns_arg * * Return: 0 */ static int tcp_splice_connect_ns(void *arg) { struct tcp_splice_connect_ns_arg *a; a = (struct tcp_splice_connect_ns_arg *)arg; ns_enter(a->c->pasta_pid); a->ret = tcp_splice_connect(a->c, a->conn, -1, a->v6, a->port); return 0; } /** * tcp_splice_new() - Handle new inbound, spliced connection * @c: Execution context * @conn: Connection pointer * @v6: Set for IPv6 connection * @port: Destination port, host order * * Return: return code from connect() */ static int tcp_splice_new(struct ctx *c, struct tcp_splice_conn *conn, int v6, in_port_t port) { struct tcp_splice_connect_ns_arg ns_arg = { c, conn, v6, port, 0 }; int *sock_pool_p, i, s = -1; if (bitmap_isset(c->tcp.port_to_tap, port)) sock_pool_p = v6 ? ns_sock_pool6 : ns_sock_pool4; else sock_pool_p = v6 ? init_sock_pool6 : init_sock_pool4; for (i = 0; i < TCP_SOCK_POOL_SIZE; i++, sock_pool_p++) { if ((s = *sock_pool_p) > 0) { *sock_pool_p = -1; break; } } if (s <= 0 && bitmap_isset(c->tcp.port_to_tap, port)) { NS_CALL(tcp_splice_connect_ns, &ns_arg); return ns_arg.ret; } return tcp_splice_connect(c, conn, s, v6, port); } /** * tcp_conn_from_sock() - Handle new connection request from listening socket * @c: Execution context * @ref: epoll reference of listening socket * @now: Current timestamp */ static void tcp_conn_from_sock(struct ctx *c, union epoll_ref ref, struct timespec *now) { union epoll_ref ref_conn = { .proto = IPPROTO_TCP, .tcp.v6 = ref.tcp.v6 }; struct sockaddr_storage sa; struct tcp_tap_conn *conn; struct epoll_event ev; socklen_t sl; int s; if (c->tcp.tap_conn_count >= MAX_TAP_CONNS) return; sl = sizeof(sa); s = accept4(ref.s, (struct sockaddr *)&sa, &sl, SOCK_NONBLOCK); if (s < 0) return; conn = &tt[c->tcp.tap_conn_count++]; ref_conn.tcp.index = conn - tt; ref_conn.s = conn->sock = s; if (ref.tcp.v6) { struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)&sa; if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr) || !memcmp(&sa6->sin6_addr, &c->addr6_seen, sizeof(c->gw6)) || !memcmp(&sa6->sin6_addr, &c->addr6, sizeof(c->gw6))) memcpy(&sa6->sin6_addr, &c->gw6, sizeof(c->gw6)); memcpy(&conn->a.a6, &sa6->sin6_addr, sizeof(conn->a.a6)); conn->sock_port = ntohs(sa6->sin6_port); conn->tap_port = ref.tcp.index; conn->seq_to_tap = tcp_seq_init(c, AF_INET6, &sa6->sin6_addr, conn->sock_port, conn->tap_port, now); conn->seq_init_to_tap = conn->seq_to_tap; tcp_hash_insert(c, conn, AF_INET6, &sa6->sin6_addr); } else { struct sockaddr_in *sa4 = (struct sockaddr_in *)&sa; in_addr_t s_addr = ntohl(sa4->sin_addr.s_addr); memset(&conn->a.a4.zero, 0, sizeof(conn->a.a4.zero)); memset(&conn->a.a4.one, 0xff, sizeof(conn->a.a4.one)); if (s_addr >> IN_CLASSA_NSHIFT == IN_LOOPBACKNET || s_addr == INADDR_ANY || s_addr == htonl(c->addr4_seen)) sa4->sin_addr.s_addr = c->gw4; memcpy(&conn->a.a4.a, &sa4->sin_addr, sizeof(conn->a.a4.a)); conn->sock_port = ntohs(sa4->sin_port); conn->tap_port = ref.tcp.index; conn->seq_to_tap = tcp_seq_init(c, AF_INET, &sa4->sin_addr, conn->sock_port, conn->tap_port, now); conn->seq_init_to_tap = conn->seq_to_tap; tcp_hash_insert(c, conn, AF_INET, &sa4->sin_addr); } conn->seq_ack_from_tap = conn->seq_to_tap + 1; conn->wnd_from_tap = WINDOW_DEFAULT; conn->ts_sock_act = conn->ts_tap_act = *now; conn->ts_ack_from_tap = conn->ts_ack_to_tap = *now; tcp_send_to_tap(c, conn, SYN, now); conn->events = ev.events = EPOLLRDHUP; ev.data.u64 = ref_conn.u64; epoll_ctl(c->epollfd, EPOLL_CTL_ADD, conn->sock, &ev); tcp_tap_state(conn, SOCK_SYN_SENT); sl = sizeof(conn->snd_buf); if (getsockopt(s, SOL_SOCKET, SO_SNDBUF, &conn->snd_buf, &sl)) conn->snd_buf = WINDOW_DEFAULT; else conn->snd_buf /= 2; } /** * tcp_sock_handler_splice() - Handler for socket mapped to spliced connection * @c: Execution context * @ref: epoll reference * @events: epoll events bitmap */ void tcp_sock_handler_splice(struct ctx *c, union epoll_ref ref, uint32_t events) { int move_from, move_to, *pipes, eof, never_read; uint8_t *rcvlowat_set, *rcvlowat_act; uint64_t *seq_read, *seq_write; struct tcp_splice_conn *conn; struct epoll_event ev; if (ref.tcp.listen) { int s, one = 1; if (c->tcp.splice_conn_count >= MAX_SPLICE_CONNS) return; if ((s = accept4(ref.s, NULL, NULL, SOCK_NONBLOCK)) < 0) return; setsockopt(s, SOL_TCP, TCP_QUICKACK, &one, sizeof(one)); conn = &ts[c->tcp.splice_conn_count++]; conn->from = s; tcp_splice_state(conn, SPLICE_ACCEPTED); if (tcp_splice_new(c, conn, ref.tcp.v6, ref.tcp.index)) tcp_splice_destroy(c, conn); return; } conn = &ts[ref.tcp.index]; if (events & EPOLLERR) goto close; if (conn->state == SPLICE_CONNECT && (events & EPOLLHUP)) goto close; if (events & EPOLLOUT) { struct epoll_event ev = { .events = EPOLLIN | EPOLLRDHUP, .data.u64 = ref.u64, }; if (conn->state == SPLICE_CONNECT) tcp_splice_connect_finish(c, conn, ref.tcp.v6); else if (conn->state == SPLICE_ESTABLISHED) epoll_ctl(c->epollfd, EPOLL_CTL_MOD, ref.s, &ev); move_to = ref.s; if (ref.s == conn->to) { move_from = conn->from; pipes = conn->pipe_from_to; } else { move_from = conn->to; pipes = conn->pipe_to_from; } } else { move_from = ref.s; if (ref.s == conn->from) { move_to = conn->to; pipes = conn->pipe_from_to; } else { move_to = conn->from; pipes = conn->pipe_to_from; } } if (events & EPOLLRDHUP) { if (ref.s == conn->from) { if (conn->state == SPLICE_ESTABLISHED) tcp_splice_state(conn, SPLICE_FIN_FROM); else if (conn->state == SPLICE_FIN_TO) tcp_splice_state(conn, SPLICE_FIN_BOTH); } else { if (conn->state == SPLICE_ESTABLISHED) tcp_splice_state(conn, SPLICE_FIN_TO); else if (conn->state == SPLICE_FIN_FROM) tcp_splice_state(conn, SPLICE_FIN_BOTH); } } swap: eof = 0; never_read = 1; if (move_from == conn->from) { seq_read = &conn->from_read; seq_write = &conn->from_written; rcvlowat_set = splice_rcvlowat_set[0]; rcvlowat_act = splice_rcvlowat_act[0]; } else { seq_read = &conn->to_read; seq_write = &conn->to_written; rcvlowat_set = splice_rcvlowat_set[1]; rcvlowat_act = splice_rcvlowat_act[1]; } while (1) { int retry_write = 0, more = 0; ssize_t read, to_write = 0, written; retry: read = splice(move_from, NULL, pipes[1], NULL, c->tcp.pipe_size, SPLICE_F_MOVE); if (read < 0) { if (errno == EINTR) goto retry; if (errno != EAGAIN) goto close; to_write = c->tcp.pipe_size; } else if (!read) { eof = 1; to_write = c->tcp.pipe_size; } else { never_read = 0; to_write += read; if (read >= (long)c->tcp.pipe_size * 90 / 100) more = SPLICE_F_MORE; if (bitmap_isset(rcvlowat_set, conn - ts)) bitmap_set(rcvlowat_act, conn - ts); } eintr: written = splice(pipes[0], NULL, move_to, NULL, to_write, SPLICE_F_MOVE | more); /* Most common case: skip updating counters. */ if (read > 0 && read == written) { if (read >= (long)c->tcp.pipe_size * 10 / 100) continue; if (!bitmap_isset(rcvlowat_set, conn - ts) && read > (long)c->tcp.pipe_size / 10) { int lowat = c->tcp.pipe_size / 4; setsockopt(move_from, SOL_SOCKET, SO_RCVLOWAT, &lowat, sizeof(lowat)); bitmap_set(rcvlowat_set, conn - ts); bitmap_set(rcvlowat_act, conn - ts); } break; } *seq_read += read > 0 ? read : 0; *seq_write += written > 0 ? written : 0; if (written < 0) { if (errno == EINTR) goto eintr; if (errno != EAGAIN) goto close; if (never_read) break; if (retry_write--) goto retry; ev.events = EPOLLIN | EPOLLOUT | EPOLLRDHUP; ref.s = move_to; ev.data.u64 = ref.u64, epoll_ctl(c->epollfd, EPOLL_CTL_MOD, move_to, &ev); break; } else if (never_read && written == (long)(c->tcp.pipe_size)) { goto retry; } else if (!never_read && written < to_write) { to_write -= written; goto retry; } if (eof) break; } if (*seq_read == *seq_write) { if (move_from == conn->from && (conn->state == SPLICE_FIN_FROM || conn->state == SPLICE_FIN_BOTH)) { if (!conn->from_fin_sent) { shutdown(conn->to, SHUT_WR); conn->from_fin_sent = 1; ev.events = 0; ref.s = move_from; ev.data.u64 = ref.u64, epoll_ctl(c->epollfd, EPOLL_CTL_MOD, move_from, &ev); } if (conn->to_fin_sent) goto close; } else if (move_from == conn->to && (conn->state == SPLICE_FIN_TO || conn->state == SPLICE_FIN_BOTH)) { if (!conn->to_fin_sent) { shutdown(conn->from, SHUT_WR); conn->to_fin_sent = 1; ev.events = 0; ref.s = move_from; ev.data.u64 = ref.u64, epoll_ctl(c->epollfd, EPOLL_CTL_MOD, move_from, &ev); } if (conn->from_fin_sent) goto close; } } if ((events & (EPOLLIN | EPOLLOUT)) == (EPOLLIN | EPOLLOUT)) { events = EPOLLIN; SWAP(move_from, move_to); if (pipes == conn->pipe_from_to) pipes = conn->pipe_to_from; else pipes = conn->pipe_from_to; goto swap; } return; close: epoll_ctl(c->epollfd, EPOLL_CTL_DEL, conn->from, NULL); epoll_ctl(c->epollfd, EPOLL_CTL_DEL, conn->to, NULL); conn->state = CLOSED; return; } /** * tcp_sock_handler() - Handle new data from socket * @c: Execution context * @ref: epoll reference * @events: epoll events bitmap * @now: Current timestamp */ void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events, struct timespec *now) { struct tcp_tap_conn *conn; if (ref.tcp.splice) { tcp_sock_handler_splice(c, ref, events); return; } if (ref.tcp.listen) { tcp_conn_from_sock(c, ref, now); return; } conn = &tt[ref.tcp.index]; conn->ts_sock_act = *now; if (events & EPOLLERR) { if (conn->state != CLOSED) tcp_rst(c, conn); return; } switch (conn->state) { case TAP_SYN_SENT: if (events & EPOLLOUT) tcp_connect_finish(c, conn, now); else tcp_rst(c, conn); return; case ESTABLISHED_SOCK_FIN: case ESTABLISHED_SOCK_FIN_SENT: case ESTABLISHED: if (events & EPOLLRDHUP) { if (conn->state == ESTABLISHED) tcp_tap_state(conn, ESTABLISHED_SOCK_FIN); } tcp_data_from_sock(c, conn, now); return; case LAST_ACK: tcp_send_to_tap(c, conn, 0, now); if (conn->seq_ack_to_tap == conn->seq_from_tap + 1 || conn->seq_ack_to_tap == conn->seq_from_tap) tcp_tap_destroy(c, conn); return; case FIN_WAIT_1: if (events & EPOLLIN) tcp_data_from_sock(c, conn, now); if (events & EPOLLRDHUP) { tcp_send_to_tap(c, conn, FIN | ACK, now); tcp_tap_state(conn, FIN_WAIT_1_SOCK_FIN); } return; case CLOSE_WAIT: case FIN_WAIT_1_SOCK_FIN: if (events & EPOLLIN) tcp_data_from_sock(c, conn, now); if (events & EPOLLHUP) { if ((conn->seq_ack_to_tap == conn->seq_from_tap + 1 || conn->seq_ack_to_tap == conn->seq_from_tap) && (conn->seq_ack_from_tap == conn->seq_to_tap - 1 || conn->seq_ack_from_tap == conn->seq_to_tap)) { tcp_tap_destroy(c, conn); } else { tcp_send_to_tap(c, conn, ACK, now); } } return; case TAP_SYN_RCVD: case SOCK_SYN_SENT: case SPLICE_ACCEPTED: case SPLICE_CONNECT: case SPLICE_ESTABLISHED: case SPLICE_FIN_FROM: case SPLICE_FIN_TO: case SPLICE_FIN_BOTH: case CLOSED: break; } } /** * tcp_set_pipe_size() - Set usable pipe size, probe starting from MAX_PIPE_SIZE * @c: Execution context */ static void tcp_set_pipe_size(struct ctx *c) { int probe_pipe[TCP_SPLICE_PIPE_POOL_SIZE * 2][2], i, j; c->tcp.pipe_size = MAX_PIPE_SIZE; smaller: for (i = 0; i < TCP_SPLICE_PIPE_POOL_SIZE * 2; i++) { if (pipe(probe_pipe[i])) { i++; break; } if (fcntl(probe_pipe[i][0], F_SETPIPE_SZ, c->tcp.pipe_size) < 0) break; } for (j = i - 1; j >= 0; j--) { close(probe_pipe[j][0]); close(probe_pipe[j][1]); } if (i == TCP_SPLICE_PIPE_POOL_SIZE * 2) return; if (!(c->tcp.pipe_size /= 2)) { c->tcp.pipe_size = MAX_PIPE_SIZE; return; } goto smaller; } /** * tcp_sock_init_one() - Initialise listening sockets for a given port * @c: Execution context * @ns: In pasta mode, if set, bind with loopback address in namespace * @port: Port, host order */ static void tcp_sock_init_one(struct ctx *c, int ns, in_port_t port) { union tcp_epoll_ref tref = { .listen = 1 }; int s; if (ns) tref.index = (in_port_t)(port + tcp_port_delta_to_init[port]); else tref.index = (in_port_t)(port + tcp_port_delta_to_tap[port]); if (c->v4) { tref.v6 = 0; tref.splice = 0; if (!ns) { s = sock_l4(c, AF_INET, IPPROTO_TCP, port, c->mode == MODE_PASTA ? BIND_EXT : BIND_ANY, tref.u32); if (s > 0) tcp_sock_set_bufsize(s); else s = -1; if (c->tcp.init_detect_ports) tcp_sock_init_ext[port][V4] = s; } if (c->mode == MODE_PASTA) { tref.splice = 1; s = sock_l4(c, AF_INET, IPPROTO_TCP, port, BIND_LOOPBACK, tref.u32); if (s > 0) tcp_sock_set_bufsize(s); else s = -1; if (c->tcp.ns_detect_ports) { if (ns) tcp_sock_ns[port][V4] = s; else tcp_sock_init_lo[port][V4] = s; } } } if (c->v6) { tref.v6 = 1; tref.splice = 0; if (!ns) { s = sock_l4(c, AF_INET6, IPPROTO_TCP, port, c->mode == MODE_PASTA ? BIND_EXT : BIND_ANY, tref.u32); if (s > 0) tcp_sock_set_bufsize(s); else s = -1; if (c->tcp.init_detect_ports) tcp_sock_init_ext[port][V6] = s; } if (c->mode == MODE_PASTA) { tref.splice = 1; s = sock_l4(c, AF_INET6, IPPROTO_TCP, port, BIND_LOOPBACK, tref.u32); if (s > 0) tcp_sock_set_bufsize(s); else s = -1; if (c->tcp.ns_detect_ports) { if (ns) tcp_sock_ns[port][V6] = s; else tcp_sock_init_lo[port][V6] = s; } } } } /** * tcp_sock_init_ns() - Bind sockets in namespace for inbound connections * @arg: Execution context * * Return: 0 on success, -1 on failure */ static int tcp_sock_init_ns(void *arg) { struct ctx *c = (struct ctx *)arg; in_port_t port; ns_enter(c->pasta_pid); for (port = 0; port < USHRT_MAX; port++) { if (!bitmap_isset(c->tcp.port_to_init, port)) continue; tcp_sock_init_one(c, 1, port); } return 0; } /** * tcp_splice_pipe_refill() - Refill pool of pre-opened pipes * @c: Execution context */ static void tcp_splice_pipe_refill(struct ctx *c) { int i; for (i = 0; i < TCP_SPLICE_PIPE_POOL_SIZE; i++) { if (splice_pipe_pool[i][0][0] > 0) break; if (pipe2(splice_pipe_pool[i][0], O_NONBLOCK)) continue; if (pipe2(splice_pipe_pool[i][1], O_NONBLOCK)) { close(splice_pipe_pool[i][1][0]); close(splice_pipe_pool[i][1][1]); continue; } fcntl(splice_pipe_pool[i][0][0], F_SETPIPE_SZ, c->tcp.pipe_size); fcntl(splice_pipe_pool[i][1][0], F_SETPIPE_SZ, c->tcp.pipe_size); } } /** * struct tcp_sock_refill_arg - Arguments for tcp_sock_refill() * @c: Execution context * @ns: Set to refill pool of sockets created in namespace */ struct tcp_sock_refill_arg { struct ctx *c; int ns; }; /** * tcp_sock_refill() - Refill pool of pre-opened sockets * @arg: See @tcp_sock_refill_arg * * Return: 0 */ static int tcp_sock_refill(void *arg) { struct tcp_sock_refill_arg *a = (struct tcp_sock_refill_arg *)arg; int i, *p4, *p6, one = 1; if (a->ns) { if (ns_enter(a->c->pasta_pid)) return 0; p4 = ns_sock_pool4; p6 = ns_sock_pool6; } else { p4 = init_sock_pool4; p6 = init_sock_pool6; } for (i = 0; a->c->v4 && i < TCP_SOCK_POOL_SIZE; i++, p4++) { if (*p4 > 0) { break; } *p4 = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP); setsockopt(*p4, SOL_TCP, TCP_QUICKACK, &one, sizeof(one)); tcp_sock_set_bufsize(*p4); } for (i = 0; a->c->v6 && i < TCP_SOCK_POOL_SIZE; i++, p6++) { if (*p6 > 0) { break; } *p6 = socket(AF_INET6, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP); setsockopt(*p6, SOL_TCP, TCP_QUICKACK, &one, sizeof(one)); tcp_sock_set_bufsize(*p6); } return 0; } /** * tcp_sock_init() - Bind sockets for inbound connections, get key for sequence * @c: Execution context * * Return: 0 on success, -1 on failure */ int tcp_sock_init(struct ctx *c, struct timespec *now) { struct tcp_sock_refill_arg refill_arg = { c, 0 }; in_port_t port; getrandom(&c->tcp.hash_secret, sizeof(c->tcp.hash_secret), GRND_RANDOM); for (port = 0; port < USHRT_MAX; port++) { if (!bitmap_isset(c->tcp.port_to_tap, port)) continue; tcp_sock_init_one(c, 0, port); } if (c->v4) tcp_sock4_iov_init(); if (c->v6) tcp_sock6_iov_init(); c->tcp.refill_ts = *now; tcp_sock_refill(&refill_arg); if (c->mode == MODE_PASTA) { tcp_set_pipe_size(c); NS_CALL(tcp_sock_init_ns, c); refill_arg.ns = 1; NS_CALL(tcp_sock_refill, &refill_arg); tcp_splice_pipe_refill(c); c->tcp.port_detect_ts = *now; } return 0; } /** * tcp_timer_one() - Handler for timed events on one socket * @c: Execution context * @conn: Connection pointer * @ts: Timestamp from caller */ static void tcp_timer_one(struct ctx *c, struct tcp_tap_conn *conn, struct timespec *ts) { int ack_from_tap = timespec_diff_ms(ts, &conn->ts_ack_from_tap); int ack_to_tap = timespec_diff_ms(ts, &conn->ts_ack_to_tap); int sock_act = timespec_diff_ms(ts, &conn->ts_sock_act); int tap_act = timespec_diff_ms(ts, &conn->ts_tap_act); int tap_data_noack; if (memcmp(&conn->tap_data_noack, &((struct timespec){ 0, 0 }), sizeof(struct timespec))) tap_data_noack = 0; else tap_data_noack = timespec_diff_ms(ts, &conn->tap_data_noack); switch (conn->state) { case CLOSED: tcp_hash_remove(conn); tcp_table_tap_compact(c, conn); break; case SOCK_SYN_SENT: case TAP_SYN_RCVD: if (ack_from_tap > SYN_TIMEOUT) tcp_rst(c, conn); break; case ESTABLISHED_SOCK_FIN_SENT: if (tap_data_noack > FIN_TIMEOUT) { tcp_rst(c, conn); break; } /* Falls through */ case ESTABLISHED: case ESTABLISHED_SOCK_FIN: if (tap_act > ACT_TIMEOUT && sock_act > ACT_TIMEOUT) { tcp_rst(c, conn); break; } if (!conn->wnd_to_tap) tcp_send_to_tap(c, conn, UPDATE_WINDOW, ts); else if (ack_to_tap > ACK_INTERVAL) tcp_send_to_tap(c, conn, 0, ts); if (tap_data_noack > ACK_TIMEOUT) { if (conn->seq_ack_from_tap < conn->seq_to_tap) { if (tap_data_noack > LAST_ACK_TIMEOUT) { tcp_rst(c, conn); break; } conn->seq_to_tap = conn->seq_ack_from_tap; tcp_data_from_sock(c, conn, ts); } } break; case CLOSE_WAIT: case FIN_WAIT_1_SOCK_FIN: if (tap_data_noack > FIN_TIMEOUT) tcp_rst(c, conn); break; case FIN_WAIT_1: if (sock_act > FIN_TIMEOUT) tcp_rst(c, conn); break; case LAST_ACK: if (sock_act > LAST_ACK_TIMEOUT) tcp_rst(c, conn); else if (tap_act > LAST_ACK_TIMEOUT) tcp_rst(c, conn); break; case TAP_SYN_SENT: case SPLICE_ACCEPTED: case SPLICE_CONNECT: case SPLICE_ESTABLISHED: case SPLICE_FIN_FROM: case SPLICE_FIN_TO: case SPLICE_FIN_BOTH: break; } } /** * struct tcp_port_detect_arg - Arguments for tcp_port_detect() * @c: Execution context * @detect_in_ns: Detect ports bound in namespace, not in init */ struct tcp_port_detect_arg { struct ctx *c; int detect_in_ns; }; /** * tcp_port_detect() - Detect ports bound in namespace or init * @arg: See struct tcp_port_detect_arg * * Return: 0 */ static int tcp_port_detect(void *arg) { struct tcp_port_detect_arg *a = (struct tcp_port_detect_arg *)arg; if (a->detect_in_ns) { ns_enter(a->c->pasta_pid); get_bound_ports(a->c, 1, IPPROTO_TCP); } else { get_bound_ports(a->c, 0, IPPROTO_TCP); } return 0; } /** * struct tcp_port_rebind_arg - Arguments for tcp_port_rebind() * @c: Execution context * @bind_in_ns: Rebind ports in namespace, not in init */ struct tcp_port_rebind_arg { struct ctx *c; int bind_in_ns; }; /** * tcp_port_rebind() - Rebind ports in namespace or init * @arg: See struct tcp_port_rebind_arg * * Return: 0 */ static int tcp_port_rebind(void *arg) { struct tcp_port_rebind_arg *a = (struct tcp_port_rebind_arg *)arg; in_port_t port; if (a->bind_in_ns) { ns_enter(a->c->pasta_pid); for (port = 0; port < USHRT_MAX; port++) { if (!bitmap_isset(a->c->tcp.port_to_init, port)) { if (tcp_sock_ns[port][V4] > 0) { close(tcp_sock_ns[port][V4]); tcp_sock_ns[port][V4] = 0; } if (tcp_sock_ns[port][V6] > 0) { close(tcp_sock_ns[port][V6]); tcp_sock_ns[port][V6] = 0; } continue; } /* Don't loop back our own ports */ if (bitmap_isset(a->c->tcp.port_to_tap, port)) continue; if ((a->c->v4 && !tcp_sock_ns[port][V4]) || (a->c->v6 && !tcp_sock_ns[port][V6])) tcp_sock_init_one(a->c, 1, port); } } else { for (port = 0; port < USHRT_MAX; port++) { if (!bitmap_isset(a->c->tcp.port_to_tap, port)) { if (tcp_sock_init_ext[port][V4] > 0) { close(tcp_sock_init_ext[port][V4]); tcp_sock_init_ext[port][V4] = 0; } if (tcp_sock_init_ext[port][V6] > 0) { close(tcp_sock_init_ext[port][V6]); tcp_sock_init_ext[port][V6] = 0; } if (tcp_sock_init_lo[port][V4] > 0) { close(tcp_sock_init_lo[port][V4]); tcp_sock_init_lo[port][V4] = 0; } if (tcp_sock_init_lo[port][V6] > 0) { close(tcp_sock_init_lo[port][V6]); tcp_sock_init_lo[port][V6] = 0; } continue; } /* Don't loop back our own ports */ if (bitmap_isset(a->c->tcp.port_to_init, port)) continue; if ((a->c->v4 && !tcp_sock_init_ext[port][V4]) || (a->c->v6 && !tcp_sock_init_ext[port][V6])) tcp_sock_init_one(a->c, 0, port); } } return 0; } /** * tcp_timer() - Scan activity bitmap for sockets waiting for timed events * @c: Execution context * @ts: Timestamp from caller */ void tcp_timer(struct ctx *c, struct timespec *now) { struct tcp_sock_refill_arg refill_arg = { c, 0 }; int i; if (c->mode == MODE_PASTA) { if (timespec_diff_ms(now, &c->tcp.port_detect_ts) > PORT_DETECT_INTERVAL) { struct tcp_port_detect_arg detect_arg = { c, 0 }; struct tcp_port_rebind_arg rebind_arg = { c, 0 }; if (c->tcp.init_detect_ports) { detect_arg.detect_in_ns = 0; tcp_port_detect(&detect_arg); rebind_arg.bind_in_ns = 1; NS_CALL(tcp_port_rebind, &rebind_arg); } if (c->tcp.ns_detect_ports) { detect_arg.detect_in_ns = 1; NS_CALL(tcp_port_detect, &detect_arg); rebind_arg.bind_in_ns = 0; tcp_port_rebind(&rebind_arg); } c->tcp.port_detect_ts = *now; } } if (timespec_diff_ms(now, &c->tcp.refill_ts) > REFILL_INTERVAL) { tcp_sock_refill(&refill_arg); if (c->mode == MODE_PASTA) { refill_arg.ns = 1; if ((c->v4 && ns_sock_pool4[TCP_SOCK_POOL_TSH] <= 0) || (c->v6 && ns_sock_pool6[TCP_SOCK_POOL_TSH] <= 0)) NS_CALL(tcp_sock_refill, &refill_arg); tcp_splice_pipe_refill(c); } } for (i = c->tcp.tap_conn_count - 1; i >= 0; i--) tcp_timer_one(c, tt + i, now); if (c->mode == MODE_PASTA) { for (i = c->tcp.splice_conn_count - 1; i >= 0; i--) { if ((ts + i)->state == CLOSED) { tcp_splice_destroy(c, ts + i); continue; } if (bitmap_isset(splice_rcvlowat_set[0], i) && !bitmap_isset(splice_rcvlowat_act[0], i)) { int lowat = 1; setsockopt((ts + i)->from, SOL_SOCKET, SO_RCVLOWAT, &lowat, sizeof(lowat)); bitmap_clear(splice_rcvlowat_set[0], i); } if (bitmap_isset(splice_rcvlowat_set[1], i) && !bitmap_isset(splice_rcvlowat_act[1], i)) { int lowat = 1; setsockopt((ts + i)->to, SOL_SOCKET, SO_RCVLOWAT, &lowat, sizeof(lowat)); bitmap_clear(splice_rcvlowat_set[1], i); } bitmap_clear(splice_rcvlowat_act[0], i); bitmap_clear(splice_rcvlowat_act[1], i); } } }