From 480aa4a10818ee25d739af2f9f156dcbbbcb64dd Mon Sep 17 00:00:00 2001 From: David Gibson Date: Mon, 6 Nov 2023 13:17:08 +1100 Subject: [PATCH] udp: Consistently use -1 to indicate un-opened sockets in maps udp uses the udp_tap_map, udp_splice_ns and udp_splice_init tables to keep track of already opened sockets bound to specific ports. We need a way to indicate entries where a socket hasn't been opened, but the code isn't consistent if this is indicated by a 0 or a -1: * udp_splice_sendfrom() and udp_tap_handler() assume that 0 indicates an unopened socket * udp_sock_init() fills in -1 for a failure to open a socket * udp_timer_one() is somewhere in between, treating only strictly positive fds as valid -1 (or, at least, negative) is really the correct choice here, since 0 is a theoretically valid fd value (if very unlikely in practice). Change to use that consistently throughout. The table does need to be initialised to all -1 values before any calls to udp_sock_init() which can happen from conf_ports(). Because C doesn't make it easy to statically initialise non zero values in large tables, this does require a somewhat awkward call to initialise the table from conf(). This is the best approach I could see for the short term, with any luck it will go away at some point when those socket tables are replaced by a unified flow table. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- conf.c | 1 + udp.c | 26 +++++++++++++++++++++----- udp.h | 1 + 3 files changed, 23 insertions(+), 5 deletions(-) diff --git a/conf.c b/conf.c index a79beb5..ad2a093 100644 --- a/conf.c +++ b/conf.c @@ -1675,6 +1675,7 @@ void conf(struct ctx *c, int argc, char **argv) c->no_map_gw = 1; /* Inbound port options can be parsed now (after IPv4/IPv6 settings) */ + udp_portmap_clear(); optind = 1; do { name = getopt_long(argc, argv, optstring, options, NULL); diff --git a/udp.c b/udp.c index e479f92..1b7650d 100644 --- a/udp.c +++ b/udp.c @@ -238,6 +238,20 @@ static struct sockaddr_in6 udp6_localname = { static struct mmsghdr udp4_mh_splice [UDP_MAX_FRAMES]; static struct mmsghdr udp6_mh_splice [UDP_MAX_FRAMES]; +/** + * udp_portmap_clear() - Clear UDP port map before configuration + */ +void udp_portmap_clear(void) +{ + unsigned i; + + for (i = 0; i < NUM_PORTS; i++) { + udp_tap_map[V4][i].sock = udp_tap_map[V6][i].sock = -1; + udp_splice_ns[V4][i].sock = udp_splice_ns[V6][i].sock = -1; + udp_splice_init[V4][i].sock = udp_splice_init[V6][i].sock = -1; + } +} + /** * udp_invert_portmap() - Compute reverse port translations for return packets * @fwd: Port forwarding configuration to compute reverse map for @@ -522,7 +536,7 @@ static void udp_splice_sendfrom(const struct ctx *c, unsigned start, unsigned n, if (from_pif == PIF_SPLICE) { src += c->udp.fwd_in.rdelta[src]; s = udp_splice_init[v6][src].sock; - if (!s && allow_new) + if (s < 0 && allow_new) s = udp_splice_new(c, v6, src, false); if (s < 0) @@ -534,7 +548,7 @@ static void udp_splice_sendfrom(const struct ctx *c, unsigned start, unsigned n, ASSERT(from_pif == PIF_HOST); src += c->udp.fwd_out.rdelta[src]; s = udp_splice_ns[v6][src].sock; - if (!s && allow_new) { + if (s < 0 && allow_new) { struct udp_splice_new_ns_arg arg = { c, v6, src, -1, }; @@ -849,7 +863,9 @@ int udp_tap_handler(struct ctx *c, uint8_t pif, s_in.sin_addr = c->ip4.addr_seen; } - if (!(s = udp_tap_map[V4][src].sock)) { + debug("UDP from tap src=%hu dst=%hu, s=%d", + src, dst, udp_tap_map[V4][src].sock); + if ((s = udp_tap_map[V4][src].sock) < 0) { union udp_epoll_ref uref = { .port = src }; in_addr_t bind_addr = { 0 }; const char *bind_if = NULL; @@ -899,7 +915,7 @@ int udp_tap_handler(struct ctx *c, uint8_t pif, bind_addr = &c->ip6.addr_ll; } - if (!(s = udp_tap_map[V6][src].sock)) { + if ((s = udp_tap_map[V6][src].sock) < 0) { union udp_epoll_ref uref = { .v6 = 1, .port = src }; const char *bind_if = NULL; @@ -1161,7 +1177,7 @@ static void udp_timer_one(struct ctx *c, int v6, enum udp_act_type type, return; } - if (s > 0) { + if (s >= 0) { epoll_ctl(c->epollfd, EPOLL_CTL_DEL, s, NULL); close(s); bitmap_clear(udp_act[v6 ? V6 : V4][type], port); diff --git a/udp.h b/udp.h index 4e45919..85ebaaa 100644 --- a/udp.h +++ b/udp.h @@ -8,6 +8,7 @@ #define UDP_TIMER_INTERVAL 1000 /* ms */ +void udp_portmap_clear(void); void udp_sock_handler(const struct ctx *c, union epoll_ref ref, uint32_t events, const struct timespec *now); int udp_tap_handler(struct ctx *c, uint8_t pif, int af,