diff options
Diffstat (limited to 'tcp.c')
| -rw-r--r-- | tcp.c | 543 |
1 files changed, 18 insertions, 525 deletions
@@ -301,24 +301,18 @@ #include "flow.h" #include "flow_table.h" +#include "tcp_internal.h" +#include "tcp_buf.h" /* Sides of a flow as we use them in "tap" connections */ #define SOCKSIDE 0 #define TAPSIDE 1 -#define TCP_FRAMES_MEM 128 -#define TCP_FRAMES \ - (c->mode == MODE_PASST ? TCP_FRAMES_MEM : 1) - #define TCP_HASH_TABLE_LOAD 70 /* % */ #define TCP_HASH_TABLE_SIZE (FLOW_MAX * 100 / TCP_HASH_TABLE_LOAD) -#define MAX_WS 8 -#define MAX_WINDOW (1 << (16 + (MAX_WS))) - /* MSS rounding: see SET_MSS() */ #define MSS_DEFAULT 536 -#define MSS (USHRT_MAX - sizeof(struct tcphdr)) #define WINDOW_DEFAULT 14600 /* RFC 6928 */ #ifdef HAS_SND_WND @@ -341,31 +335,9 @@ */ #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) - -#define FIN (1 << 0) -#define SYN (1 << 1) -#define RST (1 << 2) -#define ACK (1 << 4) -/* Flags for internal usage */ -#define DUP_ACK (1 << 5) #define ACK_IF_NEEDED 0 /* See tcp_buf_send_flag() */ -#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 - -#define CONN_V4(conn) (!!inany_v4(&(conn)->faddr)) -#define CONN_V6(conn) (!CONN_V4(conn)) + #define CONN_IS_CLOSING(conn) \ ((conn->events & ESTABLISHED) && \ (conn->events & (SOCK_FIN_RCVD | TAP_FIN_RCVD))) @@ -402,86 +374,6 @@ static int tcp_sock_ns [NUM_PORTS][IP_VERSIONS]; */ static union inany_addr low_rtt_dst[LOW_RTT_TABLE_SIZE]; -/** - * tcp_buf_seq_update - Sequences to update with length of frames once sent - * @seq: Pointer to sequence number sent to tap-side, to be updated - * @len: TCP payload length - */ -struct tcp_buf_seq_update { - uint32_t *seq; - uint16_t len; -}; - -/* Static buffers */ -/** - * tcp_l2_flags_t - TCP header and data to send option flags - * @th: TCP header - * @opts TCP option flags - */ -struct tcp_l2_flags_t { - struct tcphdr th; - char opts[OPT_MSS_LEN + OPT_WS_LEN + 1]; -}; -/** - * tcp_l2_payload_t - TCP header and data to send data - * 32 bytes aligned to be able to use AVX2 checksum - * @th: TCP header - * @data: TCP data - */ -struct tcp_l2_payload_t { - struct tcphdr th; /* 20 bytes */ - uint8_t data[MSS]; /* 65516 bytes */ -#ifdef __AVX2__ -} __attribute__ ((packed, aligned(32))); -#else -} __attribute__ ((packed, aligned(__alignof__(unsigned int)))); -#endif - -/* Ethernet header for IPv4 frames */ -static struct ethhdr tcp4_eth_src; - -/* IPv4 headers */ -static struct iphdr tcp4_l2_ip[TCP_FRAMES_MEM]; -/* TCP headers and data for IPv4 frames */ -static struct tcp_l2_payload_t tcp4_l2_payload[TCP_FRAMES_MEM]; - -static struct tcp_buf_seq_update tcp4_l2_buf_seq_update[TCP_FRAMES_MEM]; -static unsigned int tcp4_l2_buf_used; - -/* IPv4 headers for TCP option flags frames */ -static struct iphdr tcp4_l2_flags_ip[TCP_FRAMES_MEM]; -/* TCP headers and option flags for IPv4 frames */ -static struct tcp_l2_flags_t tcp4_l2_flags[TCP_FRAMES_MEM]; - -static unsigned int tcp4_l2_flags_buf_used; - -/* Ethernet header for IPv6 frames */ -static struct ethhdr tcp6_eth_src; - -/* IPv6 headers */ -static struct ipv6hdr tcp6_l2_ip[TCP_FRAMES_MEM]; -/* TCP headers and data for IPv6 frames */ -static struct tcp_l2_payload_t tcp6_l2_payload[TCP_FRAMES_MEM]; - -static struct tcp_buf_seq_update tcp6_l2_buf_seq_update[TCP_FRAMES_MEM]; -static unsigned int tcp6_l2_buf_used; - -/* IPv6 headers for TCP option flags frames */ -static struct ipv6hdr tcp6_l2_flags_ip[TCP_FRAMES_MEM]; -/* TCP headers and option flags for IPv6 frames */ -static struct tcp_l2_flags_t tcp6_l2_flags[TCP_FRAMES_MEM]; - -static unsigned int tcp6_l2_flags_buf_used; - -/* recvmsg()/sendmsg() data for tap */ -static char tcp_buf_discard [MAX_WINDOW]; -static struct iovec iov_sock [TCP_FRAMES_MEM + 1]; - -static struct iovec tcp4_l2_iov [TCP_FRAMES_MEM][TCP_IOV_NUM]; -static struct iovec tcp6_l2_iov [TCP_FRAMES_MEM][TCP_IOV_NUM]; -static struct iovec tcp4_l2_flags_iov [TCP_FRAMES_MEM][TCP_IOV_NUM]; -static struct iovec tcp6_l2_flags_iov [TCP_FRAMES_MEM][TCP_IOV_NUM]; - /* sendmsg() to socket */ static struct iovec tcp_iov [UIO_MAXIOV]; @@ -525,14 +417,6 @@ static uint32_t tcp_conn_epoll_events(uint8_t events, uint8_t conn_flags) return EPOLLRDHUP; } -static void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, - unsigned long flag); -#define conn_flag(c, conn, flag) \ - do { \ - flow_trace(conn, "flag at %s:%i", __func__, __LINE__); \ - conn_flag_do(c, conn, flag); \ - } while (0) - /** * tcp_epoll_ctl() - Add/modify/delete epoll state from connection events * @c: Execution context @@ -644,8 +528,8 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn) * @conn: Connection pointer * @flag: Flag to set, or ~flag to unset */ -static void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, - unsigned long flag) +void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn, + unsigned long flag) { if (flag & (flag - 1)) { int flag_index = fls(~flag); @@ -695,8 +579,8 @@ static void tcp_hash_remove(const struct ctx *c, * @conn: Connection pointer * @event: Connection event */ -static void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn, - unsigned long event) +void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn, + unsigned long event) { int prev, new, num = fls(event); @@ -744,12 +628,6 @@ static void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn, tcp_timer_ctl(c, conn); } -#define conn_event(c, conn, event) \ - do { \ - flow_trace(conn, "event at %s:%i", __func__, __LINE__); \ - conn_event_do(c, conn, event); \ - } while (0) - /** * tcp_rtt_dst_low() - Check if low RTT was seen for connection endpoint * @conn: Connection pointer @@ -880,107 +758,6 @@ static void tcp_update_check_tcp6(struct ipv6hdr *ip6h, struct tcphdr *th) } /** - * tcp_buf_update_l2() - Update L2 buffers with Ethernet and IPv4 addresses - * @eth_d: Ethernet destination address, NULL if unchanged - * @eth_s: Ethernet source address, NULL if unchanged - */ -void tcp_buf_update_l2(const unsigned char *eth_d, const unsigned char *eth_s) -{ - eth_update_mac(&tcp4_eth_src, eth_d, eth_s); - eth_update_mac(&tcp6_eth_src, eth_d, eth_s); -} - -/** - * tcp_buf_sock4_iov_init() - Initialise scatter-gather L2 buffers for IPv4 sockets - * @c: Execution context - */ -static void tcp_buf_sock4_iov_init(const struct ctx *c) -{ - struct iphdr iph = L2_BUF_IP4_INIT(IPPROTO_TCP); - int i; - - (void)c; - - tcp4_eth_src.h_proto = htons_constant(ETH_P_IP); - for (i = 0; i < TCP_FRAMES_MEM; i++) { - struct iovec *iov; - - /* headers */ - tcp4_l2_ip[i] = iph; - tcp4_l2_payload[i].th = (struct tcphdr){ - .doff = sizeof(struct tcphdr) / 4, - .ack = 1 - }; - - tcp4_l2_flags_ip[i] = iph; - tcp4_l2_flags[i].th = (struct tcphdr){ - .doff = sizeof(struct tcphdr) / 4, - .ack = 1 - }; - - /* iovecs */ - iov = tcp4_l2_iov[i]; - iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src; - iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr); - iov[TCP_IOV_IP].iov_base = &tcp4_l2_ip[i]; - iov[TCP_IOV_IP].iov_len = sizeof(struct iphdr); - iov[TCP_IOV_PAYLOAD].iov_base = &tcp4_l2_payload[i]; - - iov = tcp4_l2_flags_iov[i]; - iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src; - iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr); - iov[TCP_IOV_IP].iov_base = &tcp4_l2_flags_ip[i]; - iov[TCP_IOV_IP].iov_len = sizeof(struct iphdr); - iov[TCP_IOV_PAYLOAD].iov_base = &tcp4_l2_flags[i]; - } -} - -/** - * tcp_buf_sock6_iov_init() - Initialise scatter-gather L2 buffers for IPv6 sockets - * @c: Execution context - */ -static void tcp_buf_sock6_iov_init(const struct ctx *c) -{ - struct ipv6hdr ip6 = L2_BUF_IP6_INIT(IPPROTO_TCP); - int i; - - (void)c; - - tcp6_eth_src.h_proto = htons_constant(ETH_P_IPV6); - for (i = 0; i < TCP_FRAMES_MEM; i++) { - struct iovec *iov; - - /* headers */ - tcp6_l2_ip[i] = ip6; - tcp6_l2_payload[i].th = (struct tcphdr){ - .doff = sizeof(struct tcphdr) / 4, - .ack = 1 - }; - - tcp6_l2_flags_ip[i] = ip6; - tcp6_l2_flags[i].th = (struct tcphdr){ - .doff = sizeof(struct tcphdr) / 4, - .ack = 1 - }; - - /* iovecs */ - iov = tcp6_l2_iov[i]; - iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src; - iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr); - iov[TCP_IOV_IP].iov_base = &tcp6_l2_ip[i]; - iov[TCP_IOV_IP].iov_len = sizeof(struct ipv6hdr); - iov[TCP_IOV_PAYLOAD].iov_base = &tcp6_l2_payload[i]; - - iov = tcp6_l2_flags_iov[i]; - iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src; - iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr); - iov[TCP_IOV_IP].iov_base = &tcp6_l2_flags_ip[i]; - iov[TCP_IOV_IP].iov_len = sizeof(struct ipv6hdr); - iov[TCP_IOV_PAYLOAD].iov_base = &tcp6_l2_flags[i]; - } -} - -/** * tcp_opt_get() - Get option, and value if any, from TCP header * @opts: Pointer to start of TCP options in header * @len: Length of buffer, excluding TCP header -- NOT checked here! @@ -1205,46 +982,6 @@ bool tcp_flow_defer(union flow *flow) return true; } -static void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn); -#define tcp_rst(c, conn) \ - do { \ - flow_dbg((conn), "TCP reset at %s:%i", __func__, __LINE__); \ - tcp_rst_do(c, conn); \ - } while (0) - -/** - * tcp_buf_l2_flags_flush() - Send out buffers for segments with no data (flags) - * @c: Execution context - */ -static void tcp_buf_l2_flags_flush(const struct ctx *c) -{ - tap_send_iov(c, tcp6_l2_flags_iov, tcp6_l2_flags_buf_used); - tcp6_l2_flags_buf_used = 0; - - tap_send_iov(c, tcp4_l2_flags_iov, tcp4_l2_flags_buf_used); - tcp4_l2_flags_buf_used = 0; -} - -/** - * tcp_buf_l2_data_flush() - Send out buffers for segments with data - * @c: Execution context - */ -static void tcp_buf_l2_data_flush(const struct ctx *c) -{ - unsigned i; - size_t m; - - m = tap_send_iov(c, tcp6_l2_iov, tcp6_l2_buf_used); - for (i = 0; i < m; i++) - *tcp6_l2_buf_seq_update[i].seq += tcp6_l2_buf_seq_update[i].len; - tcp6_l2_buf_used = 0; - - m = tap_send_iov(c, tcp4_l2_iov, tcp4_l2_buf_used); - for (i = 0; i < m; i++) - *tcp4_l2_buf_seq_update[i].seq += tcp4_l2_buf_seq_update[i].len; - tcp4_l2_buf_used = 0; -} - /** * tcp_defer_handler() - Handler for TCP deferred tasks * @c: Execution context @@ -1291,7 +1028,7 @@ static void tcp_fill_header(struct tcphdr *th, * * Return: The total length of the IPv4 packet, host order */ -static size_t tcp_fill_headers4(const struct ctx *c, +size_t tcp_fill_headers4(const struct ctx *c, const struct tcp_tap_conn *conn, struct iphdr *iph, struct tcphdr *th, size_t plen, const uint16_t *check, @@ -1329,10 +1066,10 @@ static size_t tcp_fill_headers4(const struct ctx *c, * * Return: The total length of the IPv6 packet, host order */ -static size_t tcp_fill_headers6(const struct ctx *c, - const struct tcp_tap_conn *conn, - struct ipv6hdr *ip6h, struct tcphdr *th, - size_t plen, uint32_t seq) +size_t tcp_fill_headers6(const struct ctx *c, + const struct tcp_tap_conn *conn, + struct ipv6hdr *ip6h, struct tcphdr *th, + size_t plen, uint32_t seq) { size_t ip_len = plen + sizeof(struct ipv6hdr) + sizeof(struct tcphdr); @@ -1367,8 +1104,8 @@ static size_t tcp_fill_headers6(const struct ctx *c, * * Return: 1 if sequence or window were updated, 0 otherwise */ -static int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn, - int force_seq, struct tcp_info *tinfo) +int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn, + int force_seq, struct tcp_info *tinfo) { uint32_t prev_wnd_to_tap = conn->wnd_to_tap << conn->ws_to_tap; uint32_t prev_ack_to_tap = conn->seq_ack_to_tap; @@ -1487,9 +1224,9 @@ static void tcp_update_seqack_from_tap(const struct ctx *c, * 0 if there is no flag to send * 1 otherwise */ -static int tcp_fill_flag_header(struct ctx *c, struct tcp_tap_conn *conn, - int flags, struct tcphdr *th, char *opts, - size_t *optlen) +int tcp_fill_flag_header(struct ctx *c, struct tcp_tap_conn *conn, + int flags, struct tcphdr *th, char *opts, + size_t *optlen) { uint32_t prev_ack_to_tap = conn->seq_ack_to_tap; uint32_t prev_wnd_to_tap = conn->wnd_to_tap; @@ -1578,77 +1315,12 @@ static int tcp_fill_flag_header(struct ctx *c, struct tcp_tap_conn *conn, return 1; } -static int tcp_buf_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags) -{ - struct tcp_l2_flags_t *payload; - struct iovec *dup_iov; - struct iovec *iov; - struct tcphdr *th; - size_t optlen = 0; - size_t ip_len; - char *data; - int ret; - - if (CONN_V4(conn)) { - iov = tcp4_l2_flags_iov[tcp4_l2_flags_buf_used++]; - dup_iov = tcp4_l2_flags_iov[tcp4_l2_flags_buf_used]; - } else { - iov = tcp6_l2_flags_iov[tcp6_l2_flags_buf_used++]; - dup_iov = tcp6_l2_flags_iov[tcp6_l2_flags_buf_used]; - } - payload = iov[TCP_IOV_PAYLOAD].iov_base; - th = &payload->th; - data = payload->opts; - - ret = tcp_fill_flag_header(c, conn, flags, th, data, &optlen); - if (ret <= 0) - return ret; - - if (CONN_V4(conn)) { - struct iphdr *iph = iov[TCP_IOV_IP].iov_base; - - ip_len = tcp_fill_headers4(c, conn, iph, th, optlen, NULL, - conn->seq_to_tap); - } else { - struct ipv6hdr *ip6h = iov[TCP_IOV_IP].iov_base; - - ip_len = tcp_fill_headers6(c, conn, ip6h, th, optlen, - conn->seq_to_tap); - } - iov[TCP_IOV_PAYLOAD].iov_len = ip_len; - - if (flags & DUP_ACK) { - int i; - for (i = 0; i < TCP_IOV_NUM; i++) { - memcpy(dup_iov[i].iov_base, iov[i].iov_base, - iov[i].iov_len); - dup_iov[i].iov_len = iov[i].iov_len; - } - } - - if (CONN_V4(conn)) { - if (flags & DUP_ACK) - tcp4_l2_flags_buf_used++; - - if (tcp4_l2_flags_buf_used > TCP_FRAMES_MEM - 2) - tcp_buf_l2_flags_flush(c); - } else { - if (flags & DUP_ACK) - tcp6_l2_flags_buf_used++; - - if (tcp6_l2_flags_buf_used > TCP_FRAMES_MEM - 2) - tcp_buf_l2_flags_flush(c); - } - - return 0; -} - /** * tcp_rst_do() - Reset a tap connection: send RST segment to tap, close socket * @c: Execution context * @conn: Connection pointer */ -static void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn) +void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn) { if (conn->events == CLOSED) return; @@ -2071,185 +1743,6 @@ static int tcp_sock_consume(const struct tcp_tap_conn *conn, uint32_t ack_seq) } /** - * tcp_data_to_tap() - Finalise (queue) highest-numbered scatter-gather buffer - * @c: Execution context - * @conn: Connection pointer - * @plen: Payload length at L4 - * @no_csum: Don't compute IPv4 checksum, use the one from previous buffer - * @seq: Sequence number to be sent - */ -static void tcp_data_to_tap(const struct ctx *c, struct tcp_tap_conn *conn, - ssize_t plen, int no_csum, uint32_t seq) -{ - uint32_t *seq_update = &conn->seq_to_tap; - struct iovec *iov; - - if (CONN_V4(conn)) { - struct iovec *iov_prev = tcp4_l2_iov[tcp4_l2_buf_used - 1]; - const uint16_t *check = NULL; - - if (no_csum) { - struct iphdr *iph = iov_prev[TCP_IOV_IP].iov_base; - check = &iph->check; - } - - tcp4_l2_buf_seq_update[tcp4_l2_buf_used].seq = seq_update; - tcp4_l2_buf_seq_update[tcp4_l2_buf_used].len = plen; - - iov = tcp4_l2_iov[tcp4_l2_buf_used++]; - iov[TCP_IOV_PAYLOAD].iov_len = tcp_fill_headers4(c, conn, - iov[TCP_IOV_IP].iov_base, - iov[TCP_IOV_PAYLOAD].iov_base, - plen, check, seq); - - if (tcp4_l2_buf_used > TCP_FRAMES_MEM - 1) - tcp_buf_l2_data_flush(c); - } else if (CONN_V6(conn)) { - tcp6_l2_buf_seq_update[tcp6_l2_buf_used].seq = seq_update; - tcp6_l2_buf_seq_update[tcp6_l2_buf_used].len = plen; - - iov = tcp6_l2_iov[tcp6_l2_buf_used++]; - iov[TCP_IOV_PAYLOAD].iov_len = tcp_fill_headers6(c, conn, - iov[TCP_IOV_IP].iov_base, - iov[TCP_IOV_PAYLOAD].iov_base, - plen, seq); - - if (tcp6_l2_buf_used > TCP_FRAMES_MEM - 1) - tcp_buf_l2_data_flush(c); - } -} - -/** - * tcp_buf_data_from_sock() - Handle new data from socket, queue to tap, in window - * @c: Execution context - * @conn: Connection pointer - * - * Return: negative on connection reset, 0 otherwise - * - * #syscalls recvmsg - */ -static int tcp_buf_data_from_sock(struct ctx *c, struct tcp_tap_conn *conn) -{ - uint32_t wnd_scaled = conn->wnd_from_tap << conn->ws_from_tap; - int fill_bufs, send_bufs = 0, last_len, iov_rem = 0; - int sendlen, len, plen, v4 = CONN_V4(conn); - int s = conn->sock, i, ret = 0; - struct msghdr mh_sock = { 0 }; - uint16_t mss = MSS_GET(conn); - uint32_t already_sent, seq; - struct iovec *iov; - - already_sent = conn->seq_to_tap - conn->seq_ack_from_tap; - - if (SEQ_LT(already_sent, 0)) { - /* RFC 761, section 2.1. */ - flow_trace(conn, "ACK sequence gap: ACK for %u, sent: %u", - conn->seq_ack_from_tap, conn->seq_to_tap); - conn->seq_to_tap = conn->seq_ack_from_tap; - already_sent = 0; - } - - if (!wnd_scaled || already_sent >= wnd_scaled) { - conn_flag(c, conn, STALLED); - conn_flag(c, conn, ACK_FROM_TAP_DUE); - return 0; - } - - /* Set up buffer descriptors we'll fill completely and partially. */ - fill_bufs = DIV_ROUND_UP(wnd_scaled - already_sent, mss); - if (fill_bufs > TCP_FRAMES) { - fill_bufs = TCP_FRAMES; - iov_rem = 0; - } else { - iov_rem = (wnd_scaled - already_sent) % mss; - } - - mh_sock.msg_iov = iov_sock; - mh_sock.msg_iovlen = fill_bufs + 1; - - iov_sock[0].iov_base = tcp_buf_discard; - iov_sock[0].iov_len = already_sent; - - if (( v4 && tcp4_l2_buf_used + fill_bufs > TCP_FRAMES_MEM) || - (!v4 && tcp6_l2_buf_used + fill_bufs > TCP_FRAMES_MEM)) { - tcp_buf_l2_data_flush(c); - - /* Silence Coverity CWE-125 false positive */ - tcp4_l2_buf_used = tcp6_l2_buf_used = 0; - } - - for (i = 0, iov = iov_sock + 1; i < fill_bufs; i++, iov++) { - if (v4) - iov->iov_base = &tcp4_l2_payload[tcp4_l2_buf_used + i].data; - else - iov->iov_base = &tcp6_l2_payload[tcp6_l2_buf_used + i].data; - iov->iov_len = mss; - } - if (iov_rem) - iov_sock[fill_bufs].iov_len = iov_rem; - - /* Receive into buffers, don't dequeue until acknowledged by guest. */ - do - len = recvmsg(s, &mh_sock, MSG_PEEK); - while (len < 0 && errno == EINTR); - - if (len < 0) - goto err; - - if (!len) { - if ((conn->events & (SOCK_FIN_RCVD | TAP_FIN_SENT)) == SOCK_FIN_RCVD) { - if ((ret = tcp_buf_send_flag(c, conn, FIN | ACK))) { - tcp_rst(c, conn); - return ret; - } - - conn_event(c, conn, TAP_FIN_SENT); - } - - return 0; - } - - sendlen = len - already_sent; - if (sendlen <= 0) { - conn_flag(c, conn, STALLED); - return 0; - } - - conn_flag(c, conn, ~STALLED); - - send_bufs = DIV_ROUND_UP(sendlen, mss); - last_len = sendlen - (send_bufs - 1) * mss; - - /* Likely, some new data was acked too. */ - tcp_update_seqack_wnd(c, conn, 0, NULL); - - /* Finally, queue to tap */ - plen = mss; - seq = conn->seq_to_tap; - for (i = 0; i < send_bufs; i++) { - int no_csum = i && i != send_bufs - 1 && tcp4_l2_buf_used; - - if (i == send_bufs - 1) - plen = last_len; - - tcp_data_to_tap(c, conn, plen, no_csum, seq); - seq += plen; - } - - conn_flag(c, conn, ACK_FROM_TAP_DUE); - - return 0; - -err: - if (errno != EAGAIN && errno != EWOULDBLOCK) { - ret = -errno; - tcp_rst(c, conn); - } - - return ret; -} - -/** * tcp_data_from_tap() - tap/guest data for established connection * @c: Execution context * @conn: Connection pointer |