This commit refactors the udp_update_hdr4() and udp_update_hdr6() functions
to improve code portability by replacing the udp_meta_t parameter with
more specific parameters for the IPv4 and IPv6 headers (iphdr/ipv6hdr)
and the source socket address (sockaddr_in/sockaddr_in6).
It also moves the tap_hdr_update() function call inside the udp_tap_send()
function not to have to pass the TAP header to udp_update_hdr4() and
udp_update_hdr6()
This refactor reduces complexity by making the functions more modular and
ensuring that each function operates on more narrowly scoped data structures.
This will facilitate future backend introduction like vhost-user.
Signed-off-by: Laurent Vivier <lvivier(a)redhat.com>
Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>
---
Notes:
v6:
- reorder declarations, align summing
v2:
- move taph out of udp_update_hdr4()/udp_update_hdr6()
udp.c | 60 +++++++++++++++++++++++++++++++++--------------------------
1 file changed, 34 insertions(+), 26 deletions(-)
diff --git a/udp.c b/udp.c
index 61e106a9f05e..5bef1af969cc 100644
--- a/udp.c
+++ b/udp.c
@@ -555,7 +555,8 @@ static void udp_splice_sendfrom(const struct ctx *c, unsigned start,
unsigned n,
/**
* udp_update_hdr4() - Update headers for one IPv4 datagram
* @c: Execution context
- * @bm: Pointer to udp_meta_t to update
+ * @ip4h: Pre-filled IPv4 header (except for tot_len and saddr)
+ * @s_in: Source socket address, filled in by recvmmsg()
* @bp: Pointer to udp_payload_t to update
* @dstport: Destination port number
* @dlen: Length of UDP payload
@@ -564,15 +565,16 @@ static void udp_splice_sendfrom(const struct ctx *c, unsigned start,
unsigned n,
* Return: size of IPv4 payload (UDP header + data)
*/
static size_t udp_update_hdr4(const struct ctx *c,
- struct udp_meta_t *bm, struct udp_payload_t *bp,
+ struct iphdr *ip4h, const struct sockaddr_in *s_in,
+ struct udp_payload_t *bp,
in_port_t dstport, size_t dlen,
const struct timespec *now)
{
- in_port_t srcport = ntohs(bm->s_in.sa4.sin_port);
const struct in_addr dst = c->ip4.addr_seen;
- struct in_addr src = bm->s_in.sa4.sin_addr;
+ in_port_t srcport = ntohs(s_in->sin_port);
size_t l4len = dlen + sizeof(bp->uh);
- size_t l3len = l4len + sizeof(bm->ip4h);
+ size_t l3len = l4len + sizeof(*ip4h);
+ struct in_addr src = s_in->sin_addr;
if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.dns_match) &&
IN4_ARE_ADDR_EQUAL(&src, &c->ip4.dns_host) && srcport == 53
&&
@@ -593,24 +595,24 @@ static size_t udp_update_hdr4(const struct ctx *c,
src = c->ip4.gw;
}
- bm->ip4h.tot_len = htons(l3len);
- bm->ip4h.daddr = dst.s_addr;
- bm->ip4h.saddr = src.s_addr;
- bm->ip4h.check = csum_ip4_header(l3len, IPPROTO_UDP, src, dst);
+ ip4h->tot_len = htons(l3len);
+ ip4h->daddr = dst.s_addr;
+ ip4h->saddr = src.s_addr;
+ ip4h->check = csum_ip4_header(l3len, IPPROTO_UDP, src, dst);
- bp->uh.source = bm->s_in.sa4.sin_port;
+ bp->uh.source = s_in->sin_port;
bp->uh.dest = htons(dstport);
bp->uh.len = htons(l4len);
csum_udp4(&bp->uh, src, dst, bp->data, dlen);
- tap_hdr_update(&bm->taph, l3len + sizeof(udp4_eth_hdr));
return l4len;
}
/**
* udp_update_hdr6() - Update headers for one IPv6 datagram
* @c: Execution context
- * @bm: Pointer to udp_meta_t to update
+ * @ip6h: Pre-filled IPv6 header (except for payload_len and addresses)
+ * @s_in: Source socket address, filled in by recvmmsg()
* @bp: Pointer to udp_payload_t to update
* @dstport: Destination port number
* @dlen: Length of UDP payload
@@ -619,13 +621,14 @@ static size_t udp_update_hdr4(const struct ctx *c,
* Return: size of IPv6 payload (UDP header + data)
*/
static size_t udp_update_hdr6(const struct ctx *c,
- struct udp_meta_t *bm, struct udp_payload_t *bp,
+ struct ipv6hdr *ip6h, struct sockaddr_in6 *s_in6,
+ struct udp_payload_t *bp,
in_port_t dstport, size_t dlen,
const struct timespec *now)
{
- const struct in6_addr *src = &bm->s_in.sa6.sin6_addr;
+ const struct in6_addr *src = &s_in6->sin6_addr;
const struct in6_addr *dst = &c->ip6.addr_seen;
- in_port_t srcport = ntohs(bm->s_in.sa6.sin6_port);
+ in_port_t srcport = ntohs(s_in6->sin6_port);
uint16_t l4len = dlen + sizeof(bp->uh);
if (IN6_IS_ADDR_LINKLOCAL(src)) {
@@ -662,19 +665,18 @@ static size_t udp_update_hdr6(const struct ctx *c,
}
- bm->ip6h.payload_len = htons(l4len);
- bm->ip6h.daddr = *dst;
- bm->ip6h.saddr = *src;
- bm->ip6h.version = 6;
- bm->ip6h.nexthdr = IPPROTO_UDP;
- bm->ip6h.hop_limit = 255;
+ ip6h->payload_len = htons(l4len);
+ ip6h->daddr = *dst;
+ ip6h->saddr = *src;
+ ip6h->version = 6;
+ ip6h->nexthdr = IPPROTO_UDP;
+ ip6h->hop_limit = 255;
- bp->uh.source = bm->s_in.sa6.sin6_port;
+ bp->uh.source = s_in6->sin6_port;
bp->uh.dest = htons(dstport);
- bp->uh.len = bm->ip6h.payload_len;
+ bp->uh.len = ip6h->payload_len;
csum_udp6(&bp->uh, src, dst, bp->data, dlen);
- tap_hdr_update(&bm->taph, l4len + sizeof(bm->ip6h) + sizeof(udp6_eth_hdr));
return l4len;
}
@@ -707,11 +709,17 @@ static void udp_tap_send(const struct ctx *c,
size_t l4len;
if (v6) {
- l4len = udp_update_hdr6(c, bm, bp, dstport,
+ l4len = udp_update_hdr6(c, &bm->ip6h,
+ &bm->s_in.sa6, bp, dstport,
udp6_l2_mh_sock[i].msg_len, now);
+ tap_hdr_update(&bm->taph, l4len + sizeof(bm->ip6h) +
+ sizeof(udp6_eth_hdr));
} else {
- l4len = udp_update_hdr4(c, bm, bp, dstport,
+ l4len = udp_update_hdr4(c, &bm->ip4h,
+ &bm->s_in.sa4, bp, dstport,
udp4_l2_mh_sock[i].msg_len, now);
+ tap_hdr_update(&bm->taph, l4len + sizeof(bm->ip4h) +
+ sizeof(udp4_eth_hdr));
}
tap_iov[i][UDP_IOV_PAYLOAD].iov_len = l4len;
}
--
2.45.2