From d0dd0242a69f4ae5be4f46030bf321eb6867b2f8 Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Mon, 10 Oct 2022 19:00:43 +0200 Subject: [PATCH] tcp, tcp_splice: Fix port remapping for inbound, spliced connections In pasta mode, when we receive a new inbound connection, we need to select a socket that was created in the namespace to proceed and connect() it to its final destination. The existing condition might pick a wrong socket, though, if the destination port is remapped, because we'll check the bitmap of inbound ports using the remapped port (stored in the epoll reference) as index, and not the original port. Instead of using the port bitmap for this purpose, store this information in the epoll reference itself, by adding a new 'outbound' bit, that's set if the listening socket was created the namespace, and unset otherwise. Then, use this bit to pick a socket on the right side. Suggested-by: David Gibson Fixes: 33482d5bf293 ("passt: Add PASTA mode, major rework") Signed-off-by: Stefano Brivio Reviewed-by: David Gibson --- tcp.c | 7 +++---- tcp.h | 2 ++ tcp_splice.c | 20 +++++++++++++------- 3 files changed, 18 insertions(+), 11 deletions(-) diff --git a/tcp.c b/tcp.c index 63153b6..0d4ce57 100644 --- a/tcp.c +++ b/tcp.c @@ -3084,15 +3084,14 @@ void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events, void tcp_sock_init(const struct ctx *c, int ns, sa_family_t af, const void *addr, const char *ifname, in_port_t port) { - union tcp_epoll_ref tref = { .tcp.listen = 1 }; + union tcp_epoll_ref tref = { .tcp.listen = 1, .tcp.outbound = ns }; const void *bind_addr; int s; - if (ns) { + if (ns) tref.tcp.index = (in_port_t)(port + c->tcp.fwd_out.delta[port]); - } else { + else tref.tcp.index = (in_port_t)(port + c->tcp.fwd_in.delta[port]); - } if (af == AF_INET || af == AF_UNSPEC) { if (!addr && c->mode == MODE_PASTA) diff --git a/tcp.h b/tcp.h index 7ba7ab7..72e7815 100644 --- a/tcp.h +++ b/tcp.h @@ -34,6 +34,7 @@ void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s, * union tcp_epoll_ref - epoll reference portion for TCP connections * @listen: Set if this file descriptor is a listening socket * @splice: Set if descriptor is associated to a spliced connection + * @outbound: Listening socket maps to outbound, spliced connection * @v6: Set for IPv6 sockets or connections * @timer: Reference is a timerfd descriptor for connection * @index: Index of connection in table, or port for bound sockets @@ -43,6 +44,7 @@ union tcp_epoll_ref { struct { uint32_t listen:1, splice:1, + outbound:1, v6:1, timer:1, index:20; diff --git a/tcp_splice.c b/tcp_splice.c index 96c31c8..99c5fa7 100644 --- a/tcp_splice.c +++ b/tcp_splice.c @@ -35,6 +35,7 @@ #include #include #include +#include #include #include #include @@ -506,19 +507,19 @@ static int tcp_splice_connect_ns(void *arg) * @c: Execution context * @conn: Connection pointer * @port: Destination port, host order + * @outbound: Connection request coming from namespace * * Return: return code from connect() */ static int tcp_splice_new(const struct ctx *c, struct tcp_splice_conn *conn, - in_port_t port) + in_port_t port, int outbound) { - struct tcp_splice_connect_ns_arg ns_arg = { c, conn, port, 0 }; int *p, i, s = -1; - if (bitmap_isset(c->tcp.fwd_in.map, port)) - p = CONN_V6(conn) ? ns_sock_pool6 : ns_sock_pool4; - else + if (outbound) p = CONN_V6(conn) ? init_sock_pool6 : init_sock_pool4; + else + p = CONN_V6(conn) ? ns_sock_pool6 : ns_sock_pool4; for (i = 0; i < TCP_SOCK_POOL_SIZE; i++, p++) { SWAP(s, *p); @@ -526,11 +527,15 @@ static int tcp_splice_new(const struct ctx *c, struct tcp_splice_conn *conn, break; } - if (s < 0 && bitmap_isset(c->tcp.fwd_in.map, port)) { + /* No socket available in namespace: create a new one for connect() */ + if (s < 0 && !outbound) { + struct tcp_splice_connect_ns_arg ns_arg = { c, conn, port, 0 }; + NS_CALL(tcp_splice_connect_ns, &ns_arg); return ns_arg.ret; } + /* Otherwise, the socket will connect on the side it was created on */ return tcp_splice_connect(c, conn, s, port); } @@ -592,7 +597,8 @@ void tcp_sock_handler_splice(struct ctx *c, union epoll_ref ref, conn->a = s; conn->flags = ref.r.p.tcp.tcp.v6 ? SOCK_V6 : 0; - if (tcp_splice_new(c, conn, ref.r.p.tcp.tcp.index)) + if (tcp_splice_new(c, conn, ref.r.p.tcp.tcp.index, + ref.r.p.tcp.tcp.outbound)) conn_flag(c, conn, CLOSING); return;