mirrors/passt
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

tcp: Fixes for early data in SOCK_SYN_SENT, closing states, clamping window

Browse source 
More details here after rebase.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Stefano Brivio 2021-09-01 16:43:13 +02:00
parent 75a7239e5b
commit 1b1b27c06a
1 changed files with 30 additions and 23 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

53
tcp.c
View file

@ -165,12 +165,13 @@
* *
* - ESTABLISHED connection established, ready for data * - ESTABLISHED connection established, ready for data
* - FIN from tap write shutdown > FIN_WAIT_1 * - FIN from tap write shutdown > FIN_WAIT_1
* - zero-sized socket read read shutdown, FIN to tap > ESTABLISHED_SOCK_FIN * - EPOLLRDHUP/EPOLLHUP read shutdown > ESTABLISHED_SOCK_FIN
* - socket error RST to tap, close socket > CLOSED * - socket error RST to tap, close socket > CLOSED
* - data timeout FIN to tap > ESTABLISHED_SOCK_FIN * - data timeout FIN to tap > ESTABLISHED_SOCK_FIN
* - RST from tap close socket > CLOSED * - RST from tap close socket > CLOSED
* *
* - ESTABLISHED_SOCK_FIN socket closing connection, FIN sent to tap * - ESTABLISHED_SOCK_FIN socket closing connection, reading half closed
* - zero-sized socket read FIN, ACK to tap > CLOSE_WAIT
* - ACK from tap > CLOSE_WAIT * - ACK from tap > CLOSE_WAIT
* - ACK timeout RST to tap, close socket > CLOSED * - ACK timeout RST to tap, close socket > CLOSED
* - RST from tap close socket > CLOSED * - RST from tap close socket > CLOSED
@ -1222,12 +1223,13 @@ static void tcp_rst(struct ctx *c, struct tcp_tap_conn *conn)
/** /**
* tcp_clamp_window() - Set window and scaling from option, clamp on socket * tcp_clamp_window() - Set window and scaling from option, clamp on socket
* @conn: Connection pointer * @conn: Connection pointer
* @th: TCP header, from tap * @th: TCP header, from tap, can be NULL if window is passed
* @len: Buffer length, at L4 * @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 * @init: Set if this is the very first segment from tap
*/ */
static void tcp_clamp_window(struct tcp_tap_conn *conn, struct tcphdr *th, static void tcp_clamp_window(struct tcp_tap_conn *conn, struct tcphdr *th,
int len, int init) int len, unsigned int window, int init)
{ {
if (init) { if (init) {
conn->ws = tcp_opt_get(th, len, OPT_WS, NULL, NULL); conn->ws = tcp_opt_get(th, len, OPT_WS, NULL, NULL);
@ -1241,7 +1243,10 @@ static void tcp_clamp_window(struct tcp_tap_conn *conn, struct tcphdr *th,
conn->tap_window = ntohs(th->window); conn->tap_window = ntohs(th->window);
conn->window_clamped = 0; conn->window_clamped = 0;
} else { } else {
unsigned int window = ntohs(th->window) << conn->ws; if (th)
window = ntohs(th->window) << conn->ws;
else
window <<= conn->ws;
if (conn->window_clamped) { if (conn->window_clamped) {
if (conn->tap_window == window) if (conn->tap_window == window)
@ -1376,7 +1381,7 @@ static void tcp_conn_from_tap(struct ctx *c, int af, void *addr,
sl = sizeof(conn->mss_guest); sl = sizeof(conn->mss_guest);
setsockopt(s, SOL_TCP, TCP_MAXSEG, &conn->mss_guest, sl); setsockopt(s, SOL_TCP, TCP_MAXSEG, &conn->mss_guest, sl);
tcp_clamp_window(conn, th, len, 1); tcp_clamp_window(conn, th, len, 0, 1);
if (af == AF_INET) { if (af == AF_INET) {
sa = (struct sockaddr *)&addr4; sa = (struct sockaddr *)&addr4;
@ -1802,10 +1807,9 @@ err:
zero_len: zero_len:
if (conn->state == FIN_WAIT_1) { if (conn->state == FIN_WAIT_1) {
tcp_tap_state(conn, FIN_WAIT_1_SOCK_FIN); tcp_tap_state(conn, FIN_WAIT_1_SOCK_FIN);
} else if (conn->state < ESTABLISHED_SOCK_FIN) { } else if (conn->state == ESTABLISHED_SOCK_FIN) {
tcp_tap_state(conn, ESTABLISHED_SOCK_FIN);
shutdown(conn->sock, SHUT_RD);
tcp_send_to_tap(c, conn, FIN | ACK, NULL, 0); tcp_send_to_tap(c, conn, FIN | ACK, NULL, 0);
tcp_tap_state(conn, CLOSE_WAIT);
} }
goto out_restore_iov; goto out_restore_iov;
@ -1838,7 +1842,7 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
struct msghdr mh = { .msg_iov = tcp_tap_iov }; struct msghdr mh = { .msg_iov = tcp_tap_iov };
uint32_t max_ack_seq = conn->seq_ack_from_tap; uint32_t max_ack_seq = conn->seq_ack_from_tap;
uint32_t seq_from_tap = conn->seq_from_tap; uint32_t seq_from_tap = conn->seq_from_tap;
uint16_t max_ack_seq_wnd; uint16_t max_ack_seq_wnd = WINDOW_DEFAULT;
ssize_t len; ssize_t len;
for (i = 0, iov_i = 0; i < count; i++) { for (i = 0, iov_i = 0; i < count; i++) {
@ -1938,6 +1942,8 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
} }
} }
tcp_clamp_window(conn, NULL, 0, max_ack_seq_wnd, 0);
if (ack) { if (ack) {
conn->ts_ack_tap = *now; conn->ts_ack_tap = *now;
tcp_sock_consume(conn, max_ack_seq); tcp_sock_consume(conn, max_ack_seq);
@ -1978,11 +1984,13 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
tcp_send_to_tap(c, conn, 0, NULL, 0); tcp_send_to_tap(c, conn, 0, NULL, 0);
fin: fin:
if (conn->state == ESTABLISHED_SOCK_FIN && ack && if (conn->state == CLOSE_WAIT && fin && ack) {
!tcp_data_from_sock(c, conn, now)) tcp_data_from_sock(c, conn, now);
tcp_tap_state(conn, CLOSE_WAIT); tcp_sock_consume(conn, conn->seq_ack_from_tap);
shutdown(conn->sock, SHUT_WR);
if (fin) { tcp_tap_state(conn, LAST_ACK);
tcp_send_to_tap(c, conn, ACK, NULL, 0);
} else if (fin) {
shutdown(conn->sock, SHUT_WR); shutdown(conn->sock, SHUT_WR);
if (conn->state == ESTABLISHED) { if (conn->state == ESTABLISHED) {
tcp_tap_state(conn, FIN_WAIT_1); tcp_tap_state(conn, FIN_WAIT_1);
@ -2034,8 +2042,6 @@ int tcp_tap_handler(struct ctx *c, int af, void *addr,
return 1; return 1;
} }
tcp_clamp_window(conn, th, len, th->syn && th->ack);
conn->ts_tap = *now; conn->ts_tap = *now;
switch (conn->state) { switch (conn->state) {
@ -2045,6 +2051,8 @@ int tcp_tap_handler(struct ctx *c, int af, void *addr,
return 1; return 1;
} }
tcp_clamp_window(conn, th, len, 0, 1);
conn->mss_guest = tcp_opt_get(th, len, OPT_MSS, NULL, NULL); conn->mss_guest = tcp_opt_get(th, len, OPT_MSS, NULL, NULL);
if (conn->mss_guest < 0) if (conn->mss_guest < 0)
conn->mss_guest = MSS_DEFAULT; conn->mss_guest = MSS_DEFAULT;
@ -2103,6 +2111,8 @@ int tcp_tap_handler(struct ctx *c, int af, void *addr,
return 1; return 1;
} }
tcp_clamp_window(conn, th, len, 0, 0);
tcp_tap_state(conn, ESTABLISHED); tcp_tap_state(conn, ESTABLISHED);
break; break;
case ESTABLISHED: case ESTABLISHED:
@ -2598,8 +2608,7 @@ void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
} }
if (conn->state == SOCK_SYN_SENT) { if (conn->state == SOCK_SYN_SENT) {
/* This can only be a socket error or a shutdown from remote */ /* This could also be a data packet already, don't reset yet. */
tcp_rst(c, conn);
return; return;
} }
@ -2614,15 +2623,13 @@ void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
return; return;
} }
if (conn->state == ESTABLISHED) if (conn->state == ESTABLISHED || conn->state == ESTABLISHED_SOCK_FIN)
tcp_data_from_sock(c, conn, now); tcp_data_from_sock(c, conn, now);
if (events & (EPOLLRDHUP | EPOLLHUP)) { if (events & (EPOLLRDHUP | EPOLLHUP)) {
if (conn->state == ESTABLISHED) { if (conn->state == ESTABLISHED) {
tcp_tap_state(conn, ESTABLISHED_SOCK_FIN); tcp_tap_state(conn, ESTABLISHED_SOCK_FIN);
shutdown(conn->sock, SHUT_RD); shutdown(conn->sock, SHUT_RD);
tcp_data_from_sock(c, conn, now);
tcp_send_to_tap(c, conn, FIN | ACK, NULL, 0);
} else if (conn->state == FIN_WAIT_1) { } else if (conn->state == FIN_WAIT_1) {
tcp_tap_state(conn, FIN_WAIT_1_SOCK_FIN); tcp_tap_state(conn, FIN_WAIT_1_SOCK_FIN);
shutdown(conn->sock, SHUT_RD); shutdown(conn->sock, SHUT_RD);