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Diffstat (limited to 'tcp.c')
-rw-r--r--tcp.c277
1 files changed, 156 insertions, 121 deletions
diff --git a/tcp.c b/tcp.c
index 76e78b1..7eef386 100644
--- a/tcp.c
+++ b/tcp.c
@@ -603,6 +603,9 @@ static struct msghdr tcp6_l2_mh_sock;
static struct mmsghdr tcp_l2_mh_tap [TCP_TAP_FRAMES];
+/* sendmsg() to socket */
+static struct iovec tcp_tap_iov [TAP_MSGS];
+
/* Bitmap, activity monitoring needed for connection via tap */
static uint8_t tcp_act[MAX_TAP_CONNS / 8] = { 0 };
@@ -1480,38 +1483,6 @@ static void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn)
}
/**
- * tcp_send_to_sock() - Send buffer to socket, update timestamp and sequence
- * @c: Execution context
- * @conn: Connection pointer
- * @data: Data buffer
- * @len: Length at L4
- * @extra_flags: Additional flags for send(), if any
- *
- * Return: negative on socket error with connection reset, 0 otherwise
- */
-static int tcp_send_to_sock(struct ctx *c, struct tcp_tap_conn *conn,
- char *data, int len, int extra_flags)
-{
- int err = send(conn->sock, data, len,
- MSG_DONTWAIT | MSG_NOSIGNAL | extra_flags);
-
- if (err < 0) {
- if (errno == EAGAIN || errno == EWOULDBLOCK) {
- tcp_send_to_tap(c, conn, ZERO_WINDOW, NULL, 0);
- return err;
- }
-
- err = errno;
- tcp_rst(c, conn);
- return -err;
- }
-
- conn->seq_from_tap += err;
-
- return 0;
-}
-
-/**
* tcp_sock_consume() - Consume (discard) data from buffer, update ACK sequence
* @conn: Connection pointer
* @ack_seq: ACK sequence, host order
@@ -1812,6 +1783,154 @@ out_restore_iov:
}
/**
+ * 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_msg *msg, int count,
+ struct timespec *now)
+{
+ struct msghdr mh = { .msg_iov = tcp_tap_iov };
+ uint32_t max_ack_seq = conn->seq_ack_from_tap;
+ uint32_t seq_from_tap = conn->seq_from_tap;
+ int i, iov_i, keep = -1, ack = 0, fin = 0;
+ ssize_t len;
+
+ for (i = 0, iov_i = 0; i < count; i++) {
+ struct tcphdr *th = (struct tcphdr *)msg[i].l4h;
+ uint32_t seq, seq_offset, ack_seq;
+ size_t len = msg[i].l4_len, off;
+ char *data;
+
+ 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 (ack_seq - conn->seq_ack_from_tap < MAX_WINDOW &&
+ ack_seq - max_ack_seq < MAX_WINDOW)
+ max_ack_seq = ack_seq;
+ }
+
+ if (th->fin)
+ fin = 1;
+
+ 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 i.e. > MAX_WINDOW)
+ */
+ if (seq_offset < MAX_WINDOW && seq + len <= seq_from_tap)
+ continue;
+
+ if (seq_offset > MAX_WINDOW) {
+ 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) {
+ i = keep + 1;
+ keep = -1;
+ }
+ }
+
+ if (ack) {
+ conn->ts_ack_tap = *now;
+ tcp_sock_consume(conn, max_ack_seq);
+ }
+
+ if (!iov_i) {
+ if (keep != -1) {
+ tcp_send_to_tap(c, conn, ACK, NULL, 0);
+ tcp_send_to_tap(c, conn, ACK, NULL, 0);
+ }
+ goto fin;
+ }
+
+ mh.msg_iovlen = iov_i;
+ len = sendmsg(conn->sock, &mh, MSG_DONTWAIT | MSG_NOSIGNAL);
+ if (len < 0) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK) {
+ tcp_send_to_tap(c, conn, ZERO_WINDOW, NULL, 0);
+ return;
+ }
+ tcp_rst(c, conn);
+ return;
+ }
+
+ if (len < (seq_from_tap - conn->seq_from_tap)) {
+ conn->seq_from_tap += len;
+ tcp_send_to_tap(c, conn, ZERO_WINDOW, NULL, 0);
+ return;
+ }
+
+ conn->seq_from_tap += len;
+ tcp_send_to_tap(c, conn, 0, NULL, 0);
+
+fin:
+ if (conn->state == ESTABLISHED_SOCK_FIN && ack &&
+ !tcp_data_from_sock(c, conn, now))
+ tcp_tap_state(conn, CLOSE_WAIT);
+
+ if (fin) {
+ shutdown(conn->sock, SHUT_WR);
+ if (conn->state == ESTABLISHED)
+ tcp_tap_state(conn, FIN_WAIT_1);
+ else
+ tcp_tap_state(conn, LAST_ACK);
+ return;
+ }
+}
+
+/**
* tcp_tap_handler() - Handle packets from tap and state transitions
* @c: Execution context
* @af: Address family, AF_INET or AF_INET6
@@ -1827,16 +1946,11 @@ int tcp_tap_handler(struct ctx *c, int af, void *addr,
{
union epoll_ref ref = { .proto = IPPROTO_TCP,
.tcp.v6 = ( af == AF_INET6 ) };
-
- /* TODO: Implement message batching for TCP */
struct tcphdr *th = (struct tcphdr *)msg[0].l4h;
- size_t len = msg[0].l4_len;
- uint32_t ack_seq;
-
+ size_t len = msg[0].l4_len, off;
struct tcp_tap_conn *conn;
struct epoll_event ev;
- size_t off, skip = 0;
- int ws, i;
+ int ws;
if (len < sizeof(*th))
return 1;
@@ -1852,41 +1966,15 @@ int tcp_tap_handler(struct ctx *c, int af, void *addr,
return 1;
}
- /* TODO: Partial ACK coalescing, merge with message coalescing */
- ack_seq = ntohl(th->ack_seq);
- for (i = 0; conn->state == ESTABLISHED && i < count; i++) {
- struct tcphdr *__th = (struct tcphdr *)msg[i].l4h;
- size_t __len = msg[i].l4_len;
-
- if (__len < sizeof(*th))
- break;
-
- off = __th->doff * 4;
- if (off < sizeof(*th) || off > __len)
- break;
-
- if (!th->ack)
- continue;
-
- if (ntohl(th->ack_seq) - ack_seq < MAX_WINDOW)
- ack_seq = ntohl(th->ack_seq);
- }
-
if (th->rst) {
tcp_tap_destroy(c, conn);
return 1;
}
- if (count == 1)
- tcp_clamp_window(conn, th, len, th->syn && th->ack);
+ tcp_clamp_window(conn, th, len, th->syn && th->ack);
conn->ts_tap = *now;
- if (ntohl(th->seq) < conn->seq_from_tap &&
- conn->seq_from_tap - ntohl(th->seq) < MAX_WINDOW) {
- skip = conn->seq_from_tap - ntohl(th->seq);
- }
-
switch (conn->state) {
case SOCK_SYN_SENT:
if (!th->syn || !th->ack) {
@@ -1951,62 +2039,9 @@ int tcp_tap_handler(struct ctx *c, int af, void *addr,
break;
case ESTABLISHED:
case ESTABLISHED_SOCK_FIN:
- conn->ts_ack_tap = *now;
-
- if (ntohl(th->ack_seq) > conn->seq_to_tap &&
- (conn->seq_to_tap - ntohl(th->ack_seq)) > MAX_WINDOW) {
- return count;
- }
-
- if (th->ack) {
- if (count == 1)
- tcp_sock_consume(conn, ack_seq);
-
- if (conn->state == ESTABLISHED_SOCK_FIN) {
- if (!tcp_data_from_sock(c, conn, now))
- tcp_tap_state(conn, CLOSE_WAIT);
- }
- }
-
- if (ntohl(th->seq) > conn->seq_from_tap) {
- tcp_send_to_tap(c, conn, ACK, NULL, 0);
- tcp_send_to_tap(c, conn, ACK, NULL, 0);
- return count;
- }
-
- if (skip < len - off &&
- tcp_send_to_sock(c, conn,
- msg[0].l4h + off + skip, len - off - skip,
- (count > 1) ? MSG_MORE : 0))
- return 1;
-
- if (count == 1)
- tcp_send_to_tap(c, conn, ACK, NULL, 0);
-
- if (th->fin) {
- shutdown(conn->sock, SHUT_WR);
- if (conn->state == ESTABLISHED)
- tcp_tap_state(conn, FIN_WAIT_1);
- else
- tcp_tap_state(conn, LAST_ACK);
- }
-
- break;
case CLOSE_WAIT:
- tcp_sock_consume(conn, ntohl(th->ack_seq));
-
- if (skip < (len - off) &&
- tcp_send_to_sock(c, conn,
- msg[0].l4h + off + skip, len - off - skip,
- th->psh ? 0 : MSG_MORE))
- break;
-
- if (th->fin) {
- shutdown(conn->sock, SHUT_WR);
- tcp_tap_state(conn, LAST_ACK);
- }
-
- break;
+ tcp_data_from_tap(c, conn, msg, count, now);
+ return count;
case FIN_WAIT_1_SOCK_FIN:
if (th->ack)
tcp_tap_destroy(c, conn);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-01 12:25:34 +0000