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tcp_vu: Share more header construction between IPv4 and IPv6 paths

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tcp_vu_send_flag() and tcp_vu_prepare() both needs to do some different
things for IPv4 vs. IPv6.  However the two paths have a number of lines of
duplicated code.  We can share those at the expense of an additional
conditional (which we might be able to simplify again later).

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
This commit is contained in:
David Gibson 2024-11-13 09:04:08 +01:00 committed by Stefano Brivio
parent 9392ea7e5a
commit 3958736de5
1 changed files with 37 additions and 52 deletions
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61
tcp_vu.c
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@ -32,6 +32,7 @@
#include "tcp_internal.h"
#include "checksum.h"
#include "vu_common.h"
#include <time.h>
static struct iovec iov_vu[VIRTQUEUE_MAX_SIZE + 1];
static struct vu_virtq_element elem[VIRTQUEUE_MAX_SIZE];
@ -96,8 +97,12 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
const struct flowside *tapside = TAPFLOW(conn);
size_t l2len, l4len, optlen, hdrlen;
struct vu_virtq_element flags_elem[2];
struct tcp_payload_t *payload;
struct ipv6hdr *ip6h = NULL;
struct iovec flags_iov[2];
struct iphdr *iph = NULL;
struct ethhdr *eh;
uint32_t seq;
int elem_cnt;
int nb_ack;
int ret;
@ -119,43 +124,20 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
memcpy(eh->h_source, c->our_tap_mac, sizeof(eh->h_source));
if (CONN_V4(conn)) {
struct tcp_payload_t *payload;
struct iphdr *iph;
uint32_t seq;
eh->h_proto = htons(ETH_P_IP);
iph = vu_ip(flags_elem[0].in_sg[0].iov_base);
*iph = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
payload = vu_payloadv4(flags_elem[0].in_sg[0].iov_base);
memset(&payload->th, 0, sizeof(payload->th));
payload->th.doff = offsetof(struct tcp_payload_t, data) / 4;
payload->th.ack = 1;
seq = conn->seq_to_tap;
ret = tcp_prepare_flags(c, conn, flags, &payload->th,
(struct tcp_syn_opts *)payload->data,
&optlen);
if (ret <= 0) {
vu_queue_rewind(vq, 1);
return ret;
}
l4len = tcp_fill_headers4(conn, NULL, iph, payload, optlen,
NULL, seq, true);
l2len = sizeof(*iph);
} else {
struct tcp_payload_t *payload;
struct ipv6hdr *ip6h;
uint32_t seq;
eh->h_proto = htons(ETH_P_IPV6);
ip6h = vu_ip(flags_elem[0].in_sg[0].iov_base);
*ip6h = (struct ipv6hdr)L2_BUF_IP6_INIT(IPPROTO_TCP);
payload = vu_payloadv6(flags_elem[0].in_sg[0].iov_base);
}
memset(&payload->th, 0, sizeof(payload->th));
payload->th.doff = offsetof(struct tcp_payload_t, data) / 4;
payload->th.ack = 1;
@ -169,6 +151,11 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
return ret;
}
if (CONN_V4(conn)) {
l4len = tcp_fill_headers4(conn, NULL, iph, payload, optlen,
NULL, seq, true);
l2len = sizeof(*iph);
} else {
l4len = tcp_fill_headers6(conn, NULL, ip6h, payload, optlen,
seq, true);
l2len = sizeof(*ip6h);
@ -301,7 +288,10 @@ static void tcp_vu_prepare(const struct ctx *c,
size_t dlen, const uint16_t **check)
{
const struct flowside *toside = TAPFLOW(conn);
struct tcp_payload_t *payload;
char *base = first->iov_base;
struct ipv6hdr *ip6h = NULL;
struct iphdr *iph = NULL;
struct ethhdr *eh;
/* we guess the first iovec provided by the guest can embed
@ -314,10 +304,8 @@ static void tcp_vu_prepare(const struct ctx *c,
memcpy(eh->h_source, c->our_tap_mac, sizeof(eh->h_source));
/* initialize header */
if (inany_v4(&toside->eaddr) && inany_v4(&toside->oaddr)) {
struct tcp_payload_t *payload;
struct iphdr *iph;
if (inany_v4(&toside->eaddr) && inany_v4(&toside->oaddr)) {
ASSERT(first[0].iov_len >= tcp_vu_hdrlen(false));
eh->h_proto = htons(ETH_P_IP);
@ -325,17 +313,7 @@ static void tcp_vu_prepare(const struct ctx *c,
iph = vu_ip(base);
*iph = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
payload = vu_payloadv4(base);
memset(&payload->th, 0, sizeof(payload->th));
payload->th.doff = offsetof(struct tcp_payload_t, data) / 4;
payload->th.ack = 1;
tcp_fill_headers4(conn, NULL, iph, payload, dlen,
*check, conn->seq_to_tap, true);
*check = &iph->check;
} else {
struct tcp_payload_t *payload;
struct ipv6hdr *ip6h;
ASSERT(first[0].iov_len >= tcp_vu_hdrlen(true));
eh->h_proto = htons(ETH_P_IPV6);
@ -344,10 +322,17 @@ static void tcp_vu_prepare(const struct ctx *c,
*ip6h = (struct ipv6hdr)L2_BUF_IP6_INIT(IPPROTO_TCP);
payload = vu_payloadv6(base);
}
memset(&payload->th, 0, sizeof(payload->th));
payload->th.doff = offsetof(struct tcp_payload_t, data) / 4;
payload->th.ack = 1;
if (inany_v4(&toside->eaddr) && inany_v4(&toside->oaddr)) {
tcp_fill_headers4(conn, NULL, iph, payload, dlen,
*check, conn->seq_to_tap, true);
*check = &iph->check;
} else {
tcp_fill_headers6(conn, NULL, ip6h, payload, dlen,
conn->seq_to_tap, true);
}