From 15be1bfd81ed6d0b708e0541429f8813ce8d0972 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 16 Jan 2024 16:16:13 +1100 Subject: [PATCH] icmp: Simplify socket expiry scanning Currently we use icmp_act[] to scan for ICMP ids which might have an open socket which could time out. However icmp_act[] contains no information that's not already in icmp_id_map[] - it's just an "index" which allows scanning for relevant entries with less cache footprint. We only scan for ICMP socket expiry every 1s, though, so it's not clear that cache footprint really matters. Furthermore, there's no strong reason we need to scan even that often - the timeout is fairly arbitrary and approximate. So, eliminate icmp_act[] in favour of directly scanning icmp_id_map[] and compensate for the cache impact by reducing the scan frequency to once every 10s. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- icmp.c | 42 ++++++++++-------------------------------- icmp.h | 2 +- 2 files changed, 11 insertions(+), 33 deletions(-) diff --git a/icmp.c b/icmp.c index 01ef34a..757ca61 100644 --- a/icmp.c +++ b/icmp.c @@ -56,9 +56,6 @@ struct icmp_id_sock { /* Indexed by ICMP echo identifier */ static struct icmp_id_sock icmp_id_map[IP_VERSIONS][ICMP_NUM_IDS]; -/* Bitmaps, activity monitoring needed for identifier */ -static uint8_t icmp_act[IP_VERSIONS][DIV_ROUND_UP(ICMP_NUM_IDS, 8)]; - /** * icmp_sock_handler() - Handle new data from IPv4 ICMP socket * @c: Execution context @@ -194,7 +191,6 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, int af, debug("ICMP: new socket %i for echo ID %i", s, id); } icmp_id_map[V4][id].ts = now->tv_sec; - bitmap_set(icmp_act[V4], id); sa.sin_addr = *(struct in_addr *)daddr; if (sendto(s, ih, sizeof(*ih) + plen, MSG_NOSIGNAL, @@ -237,7 +233,6 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, int af, debug("ICMPv6: new socket %i for echo ID %i", s, id); } icmp_id_map[V6][id].ts = now->tv_sec; - bitmap_set(icmp_act[V6], id); sa.sin6_addr = *(struct in6_addr *)daddr; if (sendto(s, ih, sizeof(*ih) + plen, MSG_NOSIGNAL, @@ -261,24 +256,19 @@ fail_sock: /** * icmp_timer_one() - Handler for timed events related to a given identifier * @c: Execution context - * @v6: Set for IPv6 echo identifier bindings - * @id: Echo identifier, host order + * @id_sock: Socket fd and activity timestamp * @now: Current timestamp */ -static void icmp_timer_one(const struct ctx *c, int v6, uint16_t id, +static void icmp_timer_one(const struct ctx *c, struct icmp_id_sock *id_sock, const struct timespec *now) { - struct icmp_id_sock *id_map = &icmp_id_map[v6 ? V6 : V4][id]; - - if (now->tv_sec - id_map->ts <= ICMP_ECHO_TIMEOUT) + if (id_sock->sock < 0 || now->tv_sec - id_sock->ts <= ICMP_ECHO_TIMEOUT) return; - bitmap_clear(icmp_act[v6 ? V6 : V4], id); - - epoll_ctl(c->epollfd, EPOLL_CTL_DEL, id_map->sock, NULL); - close(id_map->sock); - id_map->sock = -1; - id_map->seq = -1; + epoll_ctl(c->epollfd, EPOLL_CTL_DEL, id_sock->sock, NULL); + close(id_sock->sock); + id_sock->sock = -1; + id_sock->seq = -1; } /** @@ -288,23 +278,11 @@ static void icmp_timer_one(const struct ctx *c, int v6, uint16_t id, */ void icmp_timer(const struct ctx *c, const struct timespec *now) { - long *word, tmp; unsigned int i; - int n, v6 = 0; -v6: - word = (long *)icmp_act[v6 ? V6 : V4]; - for (i = 0; i < ARRAY_SIZE(icmp_act); i += sizeof(long), word++) { - tmp = *word; - while ((n = ffsl(tmp))) { - tmp &= ~(1UL << (n - 1)); - icmp_timer_one(c, v6, i * 8 + n - 1, now); - } - } - - if (!v6) { - v6 = 1; - goto v6; + for (i = 0; i < ICMP_NUM_IDS; i++) { + icmp_timer_one(c, &icmp_id_map[V4][i], now); + icmp_timer_one(c, &icmp_id_map[V6][i], now); } } diff --git a/icmp.h b/icmp.h index 1a08594..4096c65 100644 --- a/icmp.h +++ b/icmp.h @@ -6,7 +6,7 @@ #ifndef ICMP_H #define ICMP_H -#define ICMP_TIMER_INTERVAL 1000 /* ms */ +#define ICMP_TIMER_INTERVAL 10000 /* ms */ struct ctx;