From 9ecf7fedc5bd9cef6e3b90e67e8a21f5074cfea7 Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Thu, 13 Jun 2024 14:36:50 +0200 Subject: tap: refactor packets handling functions Consolidate pool_tap4() and pool_tap6() into tap_flush_pools(), and tap4_handler() and tap6_handler() into tap_handler(). Create a generic tap_add_packet() to consolidate packet addition logic and reduce code duplication. The purpose is to ease the export of these functions to use them with the vhost-user backend. Signed-off-by: Laurent Vivier Signed-off-by: Stefano Brivio --- tap.c | 110 +++++++++++++++++++++++++++++++++++++----------------------------- tap.h | 3 ++ 2 files changed, 64 insertions(+), 49 deletions(-) diff --git a/tap.c b/tap.c index 26084b4..46ea24a 100644 --- a/tap.c +++ b/tap.c @@ -921,6 +921,58 @@ append: return in->count; } +/** + * tap_flush_pools() - Flush both IPv4 and IPv6 packet pools + */ +void tap_flush_pools(void) +{ + pool_flush(pool_tap4); + pool_flush(pool_tap6); +} + +/** + * tap_handler() - IPv4/IPv6 and ARP packet handler for tap file descriptor + * @c: Execution context + * @now: Current timestamp + */ +void tap_handler(struct ctx *c, const struct timespec *now) +{ + tap4_handler(c, pool_tap4, now); + tap6_handler(c, pool_tap6, now); +} + +/** + * tap_add_packet() - Queue/capture packet, update notion of guest MAC address + * @c: Execution context + * @l2len: Total L2 packet length + * @p: Packet buffer + */ +void tap_add_packet(struct ctx *c, ssize_t l2len, char *p) +{ + const struct ethhdr *eh; + + pcap(p, l2len); + + eh = (struct ethhdr *)p; + + if (memcmp(c->mac_guest, eh->h_source, ETH_ALEN)) { + memcpy(c->mac_guest, eh->h_source, ETH_ALEN); + proto_update_l2_buf(c->mac_guest, NULL); + } + + switch (ntohs(eh->h_proto)) { + case ETH_P_ARP: + case ETH_P_IP: + packet_add(pool_tap4, l2len, p); + break; + case ETH_P_IPV6: + packet_add(pool_tap6, l2len, p); + break; + default: + break; + } +} + /** * tap_sock_reset() - Handle closing or failure of connect AF_UNIX socket * @c: Execution context @@ -947,7 +999,6 @@ static void tap_sock_reset(struct ctx *c) void tap_handler_passt(struct ctx *c, uint32_t events, const struct timespec *now) { - const struct ethhdr *eh; ssize_t n, rem; char *p; @@ -960,8 +1011,7 @@ redo: p = pkt_buf; rem = 0; - pool_flush(pool_tap4); - pool_flush(pool_tap6); + tap_flush_pools(); n = recv(c->fd_tap, p, TAP_BUF_FILL, MSG_DONTWAIT); if (n < 0) { @@ -988,38 +1038,18 @@ redo: /* Complete the partial read above before discarding a malformed * frame, otherwise the stream will be inconsistent. */ - if (l2len < (ssize_t)sizeof(*eh) || + if (l2len < (ssize_t)sizeof(struct ethhdr) || l2len > (ssize_t)ETH_MAX_MTU) goto next; - pcap(p, l2len); - - eh = (struct ethhdr *)p; - - if (memcmp(c->mac_guest, eh->h_source, ETH_ALEN)) { - memcpy(c->mac_guest, eh->h_source, ETH_ALEN); - proto_update_l2_buf(c->mac_guest, NULL); - } - - switch (ntohs(eh->h_proto)) { - case ETH_P_ARP: - case ETH_P_IP: - packet_add(pool_tap4, l2len, p); - break; - case ETH_P_IPV6: - packet_add(pool_tap6, l2len, p); - break; - default: - break; - } + tap_add_packet(c, l2len, p); next: p += l2len; n -= l2len; } - tap4_handler(c, pool_tap4, now); - tap6_handler(c, pool_tap6, now); + tap_handler(c, now); /* We can't use EPOLLET otherwise. */ if (rem) @@ -1044,35 +1074,18 @@ void tap_handler_pasta(struct ctx *c, uint32_t events, redo: n = 0; - pool_flush(pool_tap4); - pool_flush(pool_tap6); + tap_flush_pools(); restart: while ((len = read(c->fd_tap, pkt_buf + n, TAP_BUF_BYTES - n)) > 0) { - const struct ethhdr *eh = (struct ethhdr *)(pkt_buf + n); - if (len < (ssize_t)sizeof(*eh) || len > (ssize_t)ETH_MAX_MTU) { + if (len < (ssize_t)sizeof(struct ethhdr) || + len > (ssize_t)ETH_MAX_MTU) { n += len; continue; } - pcap(pkt_buf + n, len); - if (memcmp(c->mac_guest, eh->h_source, ETH_ALEN)) { - memcpy(c->mac_guest, eh->h_source, ETH_ALEN); - proto_update_l2_buf(c->mac_guest, NULL); - } - - switch (ntohs(eh->h_proto)) { - case ETH_P_ARP: - case ETH_P_IP: - packet_add(pool_tap4, len, pkt_buf + n); - break; - case ETH_P_IPV6: - packet_add(pool_tap6, len, pkt_buf + n); - break; - default: - break; - } + tap_add_packet(c, len, pkt_buf + n); if ((n += len) == TAP_BUF_BYTES) break; @@ -1083,8 +1096,7 @@ restart: ret = errno; - tap4_handler(c, pool_tap4, now); - tap6_handler(c, pool_tap6, now); + tap_handler(c, now); if (len > 0 || ret == EAGAIN) return; diff --git a/tap.h b/tap.h index 2285a87..d496bd0 100644 --- a/tap.h +++ b/tap.h @@ -70,5 +70,8 @@ void tap_handler_passt(struct ctx *c, uint32_t events, const struct timespec *now); int tap_sock_unix_open(char *sock_path); void tap_sock_init(struct ctx *c); +void tap_flush_pools(void); +void tap_handler(struct ctx *c, const struct timespec *now); +void tap_add_packet(struct ctx *c, ssize_t l2len, char *p); #endif /* TAP_H */ -- cgit v1.2.3