From 87e6a464429372dfaa7212b61e5062dad87179dc Mon Sep 17 00:00:00 2001 From: Jon Maloy Date: Thu, 6 Mar 2025 13:00:05 -0500 Subject: tap: break out building of udp header from tap_udp6_send function We will need to build the UDP header at other locations than in function tap_udp6_send(), so we break that part out to a separate function. Reviewed-by: David Gibson Signed-off-by: Jon Maloy Signed-off-by: Stefano Brivio --- tap.c | 40 +++++++++++++++++++++++++++++++--------- tap.h | 4 ++++ 2 files changed, 35 insertions(+), 9 deletions(-) diff --git a/tap.c b/tap.c index 57d0795..7082620 100644 --- a/tap.c +++ b/tap.c @@ -265,7 +265,7 @@ void *tap_push_ip6h(struct ipv6hdr *ip6h, } /** - * tap_udp6_send() - Send UDP over IPv6 packet + * tap_push_uh6() - Build UDPv6 header with checksum * @c: Execution context * @src: IPv6 source address * @sport: UDP source port @@ -274,18 +274,15 @@ void *tap_push_ip6h(struct ipv6hdr *ip6h, * @flow: Flow label * @in: UDP payload contents (not including UDP header) * @dlen: UDP payload length (not including UDP header) + * + * Return: pointer at which to write the packet's payload */ -void tap_udp6_send(const struct ctx *c, +void *tap_push_uh6(struct udphdr *uh, const struct in6_addr *src, in_port_t sport, const struct in6_addr *dst, in_port_t dport, - uint32_t flow, void *in, size_t dlen) + void *in, size_t dlen) { size_t l4len = dlen + sizeof(struct udphdr); - char buf[USHRT_MAX]; - struct ipv6hdr *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6); - struct udphdr *uh = tap_push_ip6h(ip6h, src, dst, - l4len, IPPROTO_UDP, flow); - char *data = (char *)(uh + 1); const struct iovec iov = { .iov_base = in, .iov_len = dlen @@ -296,8 +293,33 @@ void tap_udp6_send(const struct ctx *c, uh->dest = htons(dport); uh->len = htons(l4len); csum_udp6(uh, src, dst, &payload); - memcpy(data, in, dlen); + return (char *)uh + sizeof(*uh); +} +/** + * tap_udp6_send() - Send UDP over IPv6 packet + * @c: Execution context + * @src: IPv6 source address + * @sport: UDP source port + * @dst: IPv6 destination address + * @dport: UDP destination port + * @flow: Flow label + * @in: UDP payload contents (not including UDP header) + * @dlen: UDP payload length (not including UDP header) + */ +void tap_udp6_send(const struct ctx *c, + const struct in6_addr *src, in_port_t sport, + const struct in6_addr *dst, in_port_t dport, + uint32_t flow, void *in, size_t dlen) +{ + size_t l4len = dlen + sizeof(struct udphdr); + char buf[USHRT_MAX]; + struct ipv6hdr *ip6h = tap_push_l2h(c, buf, ETH_P_IPV6); + struct udphdr *uh = tap_push_ip6h(ip6h, src, dst, + l4len, IPPROTO_UDP, flow); + char *data = tap_push_uh6(uh, src, sport, dst, dport, in, dlen); + + memcpy(data, in, dlen); tap_send_single(c, buf, dlen + (data - buf)); } diff --git a/tap.h b/tap.h index 9ac17ce..b53a5b8 100644 --- a/tap.h +++ b/tap.h @@ -50,6 +50,10 @@ void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src, void *tap_push_uh4(struct udphdr *uh, struct in_addr src, in_port_t sport, struct in_addr dst, in_port_t dport, const void *in, size_t dlen); +void *tap_push_uh6(struct udphdr *uh, + const struct in6_addr *src, in_port_t sport, + const struct in6_addr *dst, in_port_t dport, + void *in, size_t dlen); void *tap_push_ip4h(struct iphdr *ip4h, struct in_addr src, struct in_addr dst, size_t l4len, uint8_t proto); void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport, -- cgit v1.2.3