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udp: Allow checksum to be disabled

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We can need not to set the UDP checksum. Add a parameter to
udp_update_hdr4() and udp_update_hdr6() to disable it.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Laurent Vivier 2024-09-18 15:13:27 +02:00 committed by Stefano Brivio
parent d836d9e345
commit 4fe5f4e813
1 changed files with 40 additions and 18 deletions
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42
udp.c
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@ -298,11 +298,13 @@ static void udp_splice_send(const struct ctx *c, size_t start, size_t n,
* @bp: Pointer to udp_payload_t to update
* @toside: Flowside for destination side
* @dlen: Length of UDP payload
* @no_udp_csum: Do not set UDP checksum
*
* Return: size of IPv4 payload (UDP header + data)
*/
static size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp,
const struct flowside *toside, size_t dlen)
const struct flowside *toside, size_t dlen,
bool no_udp_csum)
{
const struct in_addr *src = inany_v4(&toside->oaddr);
const struct in_addr *dst = inany_v4(&toside->eaddr);
@ -319,6 +321,9 @@ static size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp,
bp->uh.source = htons(toside->oport);
bp->uh.dest = htons(toside->eport);
bp->uh.len = htons(l4len);
if (no_udp_csum)
bp->uh.check = 0;
else
csum_udp4(&bp->uh, *src, *dst, bp->data, dlen);
return l4len;
@ -326,15 +331,18 @@ static size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp,
/**
* udp_update_hdr6() - Update headers for one IPv6 datagram
* @ip6h: Pre-filled IPv6 header (except for payload_len and addresses)
* @ip6h: Pre-filled IPv6 header (except for payload_len and
* addresses)
* @bp: Pointer to udp_payload_t to update
* @toside: Flowside for destination side
* @dlen: Length of UDP payload
* @no_udp_csum: Do not set UDP checksum
*
* Return: size of IPv6 payload (UDP header + data)
*/
static size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp,
const struct flowside *toside, size_t dlen)
const struct flowside *toside, size_t dlen,
bool no_udp_csum)
{
uint16_t l4len = dlen + sizeof(bp->uh);
@ -348,7 +356,16 @@ static size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp,
bp->uh.source = htons(toside->oport);
bp->uh.dest = htons(toside->eport);
bp->uh.len = ip6h->payload_len;
csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6, bp->data, dlen);
if (no_udp_csum) {
/* 0 is an invalid checksum for UDP IPv6 and dropped by
* the kernel stack, even if the checksum is disabled by virtio
* flags. We need to put any non-zero value here.
*/
bp->uh.check = 0xffff;
} else {
csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6,
bp->data, dlen);
}
return l4len;
}
@ -358,9 +375,11 @@ static size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp,
* @mmh: Receiving mmsghdr array
* @idx: Index of the datagram to prepare
* @toside: Flowside for destination side
* @no_udp_csum: Do not set UDP checksum
*/
static void udp_tap_prepare(const struct mmsghdr *mmh, unsigned idx,
const struct flowside *toside)
static void udp_tap_prepare(const struct mmsghdr *mmh,
unsigned idx, const struct flowside *toside,
bool no_udp_csum)
{
struct iovec (*tap_iov)[UDP_NUM_IOVS] = &udp_l2_iov[idx];
struct udp_payload_t *bp = &udp_payload[idx];
@ -368,13 +387,15 @@ static void udp_tap_prepare(const struct mmsghdr *mmh, unsigned idx,
size_t l4len;
if (!inany_v4(&toside->eaddr) || !inany_v4(&toside->oaddr)) {
l4len = udp_update_hdr6(&bm->ip6h, bp, toside, mmh[idx].msg_len);
l4len = udp_update_hdr6(&bm->ip6h, bp, toside,
mmh[idx].msg_len, no_udp_csum);
tap_hdr_update(&bm->taph, l4len + sizeof(bm->ip6h) +
sizeof(udp6_eth_hdr));
(*tap_iov)[UDP_IOV_ETH] = IOV_OF_LVALUE(udp6_eth_hdr);
(*tap_iov)[UDP_IOV_IP] = IOV_OF_LVALUE(bm->ip6h);
} else {
l4len = udp_update_hdr4(&bm->ip4h, bp, toside, mmh[idx].msg_len);
l4len = udp_update_hdr4(&bm->ip4h, bp, toside,
mmh[idx].msg_len, no_udp_csum);
tap_hdr_update(&bm->taph, l4len + sizeof(bm->ip4h) +
sizeof(udp4_eth_hdr));
(*tap_iov)[UDP_IOV_ETH] = IOV_OF_LVALUE(udp4_eth_hdr);
@ -565,7 +586,8 @@ void udp_listen_sock_handler(const struct ctx *c, union epoll_ref ref,
udp_splice_prepare(udp_mh_recv, i);
} else if (batchpif == PIF_TAP) {
udp_tap_prepare(udp_mh_recv, i,
flowside_at_sidx(batchsidx));
flowside_at_sidx(batchsidx),
false);
}
if (++i >= n)
@ -636,7 +658,7 @@ void udp_reply_sock_handler(const struct ctx *c, union epoll_ref ref,
if (pif_is_socket(topif))
udp_splice_prepare(udp_mh_recv, i);
else if (topif == PIF_TAP)
udp_tap_prepare(udp_mh_recv, i, toside);
udp_tap_prepare(udp_mh_recv, i, toside, false);
/* Restore sockaddr length clobbered by recvmsg() */
udp_mh_recv[i].msg_hdr.msg_namelen = sizeof(udp_meta[i].s_in);
}