diff options
| -rw-r--r-- | tcp.c | 59 |
1 files changed, 59 insertions, 0 deletions
@@ -369,6 +369,9 @@ #define PORT_DETECT_INTERVAL 1000 +#define LOW_RTT_TABLE_SIZE 8 +#define LOW_RTT_THRESHOLD 5 /* us */ + /* We need to include <linux/tcp.h> for tcpi_bytes_acked, instead of * <netinet/tcp.h>, but that doesn't include a definition for SOL_TCP */ @@ -440,6 +443,7 @@ struct tcp_tap_conn; * @a.a4.a: IPv4 address * @tap_port: Guest-facing tap port * @sock_port: Remote, socket-facing port + * @local: Destination is local * @state: TCP connection state * @seq_to_tap: Next sequence for packets to tap * @seq_ack_from_tap: Last ACK number received from tap @@ -476,6 +480,7 @@ struct tcp_tap_conn { } a; in_port_t tap_port; in_port_t sock_port; + int local; enum tcp_state state; uint32_t seq_to_tap; @@ -536,6 +541,9 @@ 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]; +/* Table of destinations with very low RTT (assumed to be local), LRU */ +static struct in6_addr low_rtt_dst[LOW_RTT_TABLE_SIZE]; + /** * tcp_remap_to_tap() - Set delta for port translation toward guest/tap * @port: Original destination port, host order @@ -681,6 +689,47 @@ static int ns_sock_pool4 [TCP_SOCK_POOL_SIZE]; static int ns_sock_pool6 [TCP_SOCK_POOL_SIZE]; /** + * tcp_rtt_dst_low() - Check if low RTT was seen for connection endpoint + * @conn: Connection pointer + * Return: 1 if destination is in low RTT table, 0 otherwise + */ +static int tcp_rtt_dst_low(struct tcp_tap_conn *conn) +{ + int i; + + for (i = 0; i < LOW_RTT_TABLE_SIZE; i++) + if (!memcmp(&conn->a.a6, low_rtt_dst + i, sizeof(conn->a.a6))) + return 1; + + return 0; +} + +/** + * tcp_rtt_dst_check() - Check tcpi_min_rtt, insert endpoint in table if low + * @conn: Connection pointer + * @info: Pointer to struct tcp_info for socket + */ +static void tcp_rtt_dst_check(struct tcp_tap_conn *conn, struct tcp_info *info) +{ + int i, hole = -1; + + if (!info->tcpi_min_rtt || (int)info->tcpi_min_rtt > LOW_RTT_THRESHOLD) + return; + + for (i = 0; i < LOW_RTT_TABLE_SIZE; i++) { + if (!memcmp(&conn->a.a6, low_rtt_dst + i, sizeof(conn->a.a6))) + return; + if (hole == -1 && IN6_IS_ADDR_UNSPECIFIED(low_rtt_dst + i)) + hole = i; + } + + memcpy(low_rtt_dst + hole++, &conn->a.a6, sizeof(conn->a.a6)); + if (hole == LOW_RTT_TABLE_SIZE) + hole = 0; + memcpy(low_rtt_dst + hole, &in6addr_any, sizeof(conn->a.a6)); +} + +/** * tcp_tap_state() - Set given TCP state for tap connection, report to stderr * @conn: Connection pointer * @state: New TCP state to be set @@ -1258,6 +1307,11 @@ static int tcp_send_to_tap(struct ctx *c, struct tcp_tap_conn *conn, int flags, mss -= sizeof(struct iphdr); else mss -= sizeof(struct ipv6hdr); + + if (!conn->local && !tcp_rtt_dst_low(conn)) + mss = MIN(mss, PAGE_SIZE); + else + mss = ROUND_DOWN(mss, PAGE_SIZE); } *(uint16_t *)data = htons(mss); @@ -1588,6 +1642,11 @@ static void tcp_conn_from_tap(struct ctx *c, int af, void *addr, tcp_hash_insert(c, conn, af, addr); + if (!bind(s, sa, sl)) + tcp_rst(c, conn); /* Nobody is listening then */ + if (errno != EADDRNOTAVAIL) + conn->local = 1; + if (connect(s, sa, sl)) { tcp_tap_state(conn, TAP_SYN_SENT); |