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udp: Unify udp[46]_l2_iov

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The only differences between these arrays are that udp4_l2_iov is
pre-initialised to point to the IPv4 ethernet header, and IPv4 per-frame
header and udp6_l2_iov points to the IPv6 versions.

We already have to set up a bunch of headers per-frame, including updating
udp[46]_l2_iov[i][UDP_IOV_PAYLOAD].iov_len.  It makes more sense to adjust
the IOV entries to point at the correct headers for the frame than to have
two complete sets of iovecs.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2024-07-05 20:44:04 +10:00 committed by Stefano Brivio
parent 9f9b15f949
commit 55aff45bc1
1 changed files with 19 additions and 23 deletions
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42
udp.c
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@ -241,8 +241,7 @@ static struct iovec udp_iov_splice [UDP_MAX_FRAMES];
static struct mmsghdr udp_mh_splice [UDP_MAX_FRAMES];
/* IOVs for L2 frames */
static struct iovec udp4_l2_iov [UDP_MAX_FRAMES][UDP_NUM_IOVS];
static struct iovec udp6_l2_iov [UDP_MAX_FRAMES][UDP_NUM_IOVS];
static struct iovec udp_l2_iov [UDP_MAX_FRAMES][UDP_NUM_IOVS];
/**
@ -305,8 +304,9 @@ void udp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s)
static void udp_iov_init_one(const struct ctx *c, size_t i)
{
struct udp_payload_t *payload = &udp_payload[i];
struct iovec *siov = &udp_iov_recv[i];
struct udp_meta_t *meta = &udp_meta[i];
struct iovec *siov = &udp_iov_recv[i];
struct iovec *tiov = udp_l2_iov[i];
*meta = (struct udp_meta_t) {
.ip4h = L2_BUF_IP4_INIT(IPPROTO_UDP),
@ -317,34 +317,29 @@ static void udp_iov_init_one(const struct ctx *c, size_t i)
udp4_eth_hdr.h_proto = htons_constant(ETH_P_IP);
udp6_eth_hdr.h_proto = htons_constant(ETH_P_IPV6);
tiov[UDP_IOV_TAP] = tap_hdr_iov(c, &meta->taph);
tiov[UDP_IOV_PAYLOAD].iov_base = payload;
/* It's useful to have separate msghdr arrays for receiving. Otherwise,
* an IPv4 recv() will alter msg_namelen, so we'd have to reset it every
* time or risk truncating the address on future IPv6 recv()s.
*/
if (c->ifi4) {
struct msghdr *mh = &udp4_mh_recv[i].msg_hdr;
struct iovec *tiov = udp4_l2_iov[i];
mh->msg_name = &meta->s_in;
mh->msg_namelen = sizeof(struct sockaddr_in);
mh->msg_iov = siov;
mh->msg_iovlen = 1;
tiov[UDP_IOV_TAP] = tap_hdr_iov(c, &meta->taph);
tiov[UDP_IOV_ETH] = IOV_OF_LVALUE(udp4_eth_hdr);
tiov[UDP_IOV_IP] = IOV_OF_LVALUE(meta->ip4h);
tiov[UDP_IOV_PAYLOAD].iov_base = payload;
}
if (c->ifi6) {
struct msghdr *mh = &udp6_mh_recv[i].msg_hdr;
struct iovec *tiov = udp6_l2_iov[i];
mh->msg_name = &meta->s_in;
mh->msg_namelen = sizeof(struct sockaddr_in6);
mh->msg_iov = siov;
mh->msg_iovlen = 1;
tiov[UDP_IOV_TAP] = tap_hdr_iov(c, &meta->taph);
tiov[UDP_IOV_ETH] = IOV_OF_LVALUE(udp6_eth_hdr);
tiov[UDP_IOV_IP] = IOV_OF_LVALUE(meta->ip6h);
tiov[UDP_IOV_PAYLOAD].iov_base = payload;
}
}
@ -729,22 +724,19 @@ static unsigned udp_tap_send(const struct ctx *c, size_t start, size_t n,
in_port_t dstport, union epoll_ref ref,
const struct timespec *now)
{
struct iovec (*tap_iov)[UDP_NUM_IOVS];
struct mmsghdr *mmh_recv;
size_t i = start;
ASSERT(udp_meta[start].splicesrc == -1);
ASSERT(ref.type == EPOLL_TYPE_UDP);
if (ref.udp.v6) {
tap_iov = udp6_l2_iov;
if (ref.udp.v6)
mmh_recv = udp6_mh_recv;
} else {
else
mmh_recv = udp4_mh_recv;
tap_iov = udp4_l2_iov;
}
do {
struct iovec (*tap_iov)[UDP_NUM_IOVS] = &udp_l2_iov[i];
struct udp_payload_t *bp = &udp_payload[i];
struct udp_meta_t *bm = &udp_meta[i];
size_t l4len;
@ -755,14 +747,18 @@ static unsigned udp_tap_send(const struct ctx *c, size_t start, size_t n,
udp6_mh_recv[i].msg_len, now);
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(c, &bm->ip4h,
&bm->s_in.sa4, bp, dstport,
udp4_mh_recv[i].msg_len, now);
tap_hdr_update(&bm->taph, l4len + sizeof(bm->ip4h) +
sizeof(udp4_eth_hdr));
(*tap_iov)[UDP_IOV_ETH] = IOV_OF_LVALUE(udp4_eth_hdr);
(*tap_iov)[UDP_IOV_IP] = IOV_OF_LVALUE(bm->ip4h);
}
tap_iov[i][UDP_IOV_PAYLOAD].iov_len = l4len;
(*tap_iov)[UDP_IOV_PAYLOAD].iov_len = l4len;
if (++i >= n)
break;
@ -770,7 +766,7 @@ static unsigned udp_tap_send(const struct ctx *c, size_t start, size_t n,
udp_meta[i].splicesrc = udp_mmh_splice_port(ref, &mmh_recv[i]);
} while (udp_meta[i].splicesrc == -1);
tap_send_frames(c, &tap_iov[start][0], UDP_NUM_IOVS, i - start);
tap_send_frames(c, &udp_l2_iov[start][0], UDP_NUM_IOVS, i - start);
return i - start;
}