From e07f539ae0aa3ad623c4e8afcaca26906fd1eb17 Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Fri, 30 Apr 2021 14:52:18 +0200 Subject: udp, passt: Introduce socket packet buffer, avoid getsockname() for UDP This is in preparation for scatter-gather IO on the UDP receive path: save a getsockname() syscall by setting a flag if we get the numbering of all bound sockets in a strict sequence (expected, in practice) and repurpose the tap buffer to be also a socket receive buffer, passing it down to protocol handlers. Signed-off-by: Stefano Brivio --- udp.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 63 insertions(+), 13 deletions(-) (limited to 'udp.c') diff --git a/udp.c b/udp.c index 1fb8406..46a3302 100644 --- a/udp.c +++ b/udp.c @@ -124,25 +124,69 @@ static void udp_sock_handler_local(struct ctx *c, int af, void *sa, } } +/** + * udp_sock_name() - Get address family and port for bound UDP socket + * @c: Execution context + * @s: File descriptor number for socket + * @port: Local port, set on return, network order + * + * Return: address family, AF_INET or AF_INET6, negative error code on failure + */ +static int udp_sock_name(struct ctx *c, int s, in_port_t *port) +{ + if (!c->udp.fd_in_seq) { + struct sockaddr_storage sa; + socklen_t sl; + + sl = sizeof(sa); + if (getsockname(s, (struct sockaddr *)&sa, &sl)) + return -errno; + + if (sa.ss_family == AF_INET) { + *port = ((struct sockaddr_in *)&sa)->sin_port; + return AF_INET; + } + + if (sa.ss_family == AF_INET6) { + *port = ((struct sockaddr_in6 *)&sa)->sin6_port; + return AF_INET6; + } + + return -ENOTSUP; + } + + if (c->v4 && c->v6) { + *port = htons((s - c->udp.fd_min) / 2); + return ((s - c->udp.fd_min) % 2) ? AF_INET6 : AF_INET; + } + + *port = htons(s - c->udp.fd_min); + return c->v4 ? AF_INET : AF_INET6; +} + /** * udp_sock_handler() - Handle new data from socket * @c: Execution context * @s: File descriptor number for socket * @events: epoll events bitmap + * @pkt_buf: Buffer to receive packets, currently unused * @now: Current timestamp */ -void udp_sock_handler(struct ctx *c, int s, uint32_t events, +void udp_sock_handler(struct ctx *c, int s, uint32_t events, char *pkt_buf, struct timespec *now) { struct in6_addr a6 = { .s6_addr = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff, 0, 0, 0, 0 } }; - struct sockaddr_storage sr, sl; + struct sockaddr_storage sr; socklen_t slen = sizeof(sr); char buf[USHRT_MAX]; struct udphdr *uh; ssize_t n; + int af; + + (void)pkt_buf; if (events == EPOLLERR) return; @@ -153,13 +197,10 @@ void udp_sock_handler(struct ctx *c, int s, uint32_t events, return; uh = (struct udphdr *)buf; + af = udp_sock_name(c, s, &uh->dest); - if (getsockname(s, (struct sockaddr *)&sl, &slen)) - return; - - if (sl.ss_family == AF_INET) { + if (af == AF_INET) { struct sockaddr_in *sr4 = (struct sockaddr_in *)&sr; - struct sockaddr_in *sl4 = (struct sockaddr_in *)&sl; if (ntohl(sr4->sin_addr.s_addr) == INADDR_LOOPBACK || ntohl(sr4->sin_addr.s_addr) == INADDR_ANY) @@ -167,19 +208,16 @@ void udp_sock_handler(struct ctx *c, int s, uint32_t events, memcpy(&a6.s6_addr[12], &sr4->sin_addr, sizeof(sr4->sin_addr)); uh->source = sr4->sin_port; - uh->dest = sl4->sin_port; uh->len = htons(n + sizeof(*uh)); tap_ip_send(c, &a6, IPPROTO_UDP, buf, n + sizeof(*uh)); - } else if (sl.ss_family == AF_INET6) { + } else if (af == AF_INET6) { struct sockaddr_in6 *sr6 = (struct sockaddr_in6 *)&sr; - struct sockaddr_in6 *sl6 = (struct sockaddr_in6 *)&sl; if (IN6_IS_ADDR_LOOPBACK(&sr6->sin6_addr)) udp_sock_handler_local(c, AF_INET6, sr6, now); uh->source = sr6->sin6_port; - uh->dest = sl6->sin6_port; uh->len = htons(n + sizeof(*uh)); tap_ip_send(c, &sr6->sin6_addr, IPPROTO_UDP, @@ -363,17 +401,23 @@ int udp_tap_handler(struct ctx *c, int af, void *addr, */ int udp_sock_init(struct ctx *c) { + int s, prev = -1; in_port_t port; - int s; c->udp.fd_min = INT_MAX; c->udp.fd_max = 0; + c->udp.fd_in_seq = 1; for (port = 0; port < USHRT_MAX; port++) { if (c->v4) { if ((s = sock_l4(c, AF_INET, IPPROTO_UDP, port)) < 0) return -1; + if (c->udp.fd_in_seq && prev != -1 && s != prev + 1) + c->udp.fd_in_seq = 0; + else + prev = s; + up4[port].s = s; } @@ -381,6 +425,11 @@ int udp_sock_init(struct ctx *c) if ((s = sock_l4(c, AF_INET6, IPPROTO_UDP, port)) < 0) return -1; + if (c->udp.fd_in_seq && prev != -1 && s != prev + 1) + c->udp.fd_in_seq = 0; + else + prev = s; + up6[port].s = s; } } @@ -424,7 +473,8 @@ static void udp_timer_one(struct ctx *c, int af, in_port_t p, if (s != -1) { epoll_ctl(c->epollfd, EPOLL_CTL_DEL, s, NULL); close(s); - sock_l4(c, af, IPPROTO_UDP, p); + if (sock_l4(c, af, IPPROTO_UDP, p) != s) + c->udp.fd_in_seq = 0; } } -- cgit v1.2.3