From 7b56117dae0f19c176d852ec7ee1f01937a994c7 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Fri, 8 Sep 2023 11:49:47 +1000 Subject: [PATCH] udp, tap: Correctly advance through packets in udp_tap_handler() In both tap4_handler() and tap6_handler(), once we've sorted incoming l3 packets into "sequences", we then step through all the packets in each DUP sequence calling udp_tap_handler(). Or so it appears. In fact, udp_tap_handler() doesn't take an index and always starts with packet 0 of the sequence, even if called repeatedly. It appears to be written with the idea that the struct pool is a queue, from which it consumes packets as it processes them, but that's not how the pool data structure works. Correct this by adding an index parameter to udp_tap_handler() and altering the loops in tap.c to step through the pool properly. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- tap.c | 20 ++++++++------------ udp.c | 15 ++++++++------- udp.h | 2 +- 3 files changed, 17 insertions(+), 20 deletions(-) diff --git a/tap.c b/tap.c index 445a5ca..93db989 100644 --- a/tap.c +++ b/tap.c @@ -707,24 +707,22 @@ append: for (j = 0, seq = tap4_l4; j < seq_count; j++, seq++) { struct pool *p = (struct pool *)&seq->p; + size_t k; tap_packet_debug(NULL, NULL, seq, 0, NULL, p->count); if (seq->protocol == IPPROTO_TCP) { - size_t k; - if (c->no_tcp) continue; for (k = 0; k < p->count; ) k += tcp_tap_handler(c, AF_INET, &seq->saddr, &seq->daddr, p, k, now); } else if (seq->protocol == IPPROTO_UDP) { - size_t n = p->count; - if (c->no_udp) continue; - while ((n -= udp_tap_handler(c, AF_INET, &seq->saddr, - &seq->daddr, p, now))); + for (k = 0; k < p->count; ) + k += udp_tap_handler(c, AF_INET, &seq->saddr, + &seq->daddr, p, k, now); } } @@ -872,25 +870,23 @@ append: for (j = 0, seq = tap6_l4; j < seq_count; j++, seq++) { struct pool *p = (struct pool *)&seq->p; + size_t k; tap_packet_debug(NULL, NULL, NULL, seq->protocol, seq, p->count); if (seq->protocol == IPPROTO_TCP) { - size_t k; - if (c->no_tcp) continue; for (k = 0; k < p->count; ) k += tcp_tap_handler(c, AF_INET6, &seq->saddr, &seq->daddr, p, k, now); } else if (seq->protocol == IPPROTO_UDP) { - size_t n = p->count; - if (c->no_udp) continue; - while ((n -= udp_tap_handler(c, AF_INET6, &seq->saddr, - &seq->daddr, p, now))); + for (k = 0; k < p->count; ) + k += udp_tap_handler(c, AF_INET6, &seq->saddr, + &seq->daddr, p, k, now); } } diff --git a/udp.c b/udp.c index f4ed660..ed1b7a5 100644 --- a/udp.c +++ b/udp.c @@ -789,6 +789,7 @@ void udp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events, * @saddr: Source address * @daddr: Destination address * @p: Pool of UDP packets, with UDP headers + * @idx: Index of first packet to process * @now: Current timestamp * * Return: count of consumed packets @@ -796,7 +797,7 @@ void udp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events, * #syscalls sendmmsg */ int udp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr, - const struct pool *p, const struct timespec *now) + const struct pool *p, int idx, const struct timespec *now) { struct mmsghdr mm[UIO_MAXIOV]; struct iovec m[UIO_MAXIOV]; @@ -811,7 +812,7 @@ int udp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr, (void)c; (void)saddr; - uh = packet_get(p, 0, 0, sizeof(*uh), NULL); + uh = packet_get(p, idx, 0, sizeof(*uh), NULL); if (!uh) return 1; @@ -859,7 +860,7 @@ int udp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr, s = sock_l4(c, AF_INET, IPPROTO_UDP, &bind_addr, bind_if, src, uref.u32); if (s < 0) - return p->count; + return p->count - idx; udp_tap_map[V4][src].sock = s; bitmap_set(udp_act[V4][UDP_ACT_TAP], src); @@ -909,7 +910,7 @@ int udp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr, s = sock_l4(c, AF_INET6, IPPROTO_UDP, bind_addr, bind_if, src, uref.u32); if (s < 0) - return p->count; + return p->count - idx; udp_tap_map[V6][src].sock = s; bitmap_set(udp_act[V6][UDP_ACT_TAP], src); @@ -918,13 +919,13 @@ int udp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr, udp_tap_map[V6][src].ts = now->tv_sec; } - for (i = 0; i < (int)p->count; i++) { + for (i = 0; i < (int)p->count - idx; i++) { struct udphdr *uh_send; size_t len; - uh_send = packet_get(p, i, 0, sizeof(*uh), &len); + uh_send = packet_get(p, idx + i, 0, sizeof(*uh), &len); if (!uh_send) - return p->count; + return p->count - idx; mm[i].msg_hdr.msg_name = sa; mm[i].msg_hdr.msg_namelen = sl; diff --git a/udp.h b/udp.h index f553de2..0ee0695 100644 --- a/udp.h +++ b/udp.h @@ -11,7 +11,7 @@ void udp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events, const struct timespec *now); int udp_tap_handler(struct ctx *c, int af, const void *saddr, const void *daddr, - const struct pool *p, const struct timespec *now); + const struct pool *p, int idx, const struct timespec *now); int udp_sock_init(const struct ctx *c, int ns, sa_family_t af, const void *addr, const char *ifname, in_port_t port); int udp_init(struct ctx *c);