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tcp: Introduce tcp_fill_headers4()/tcp_fill_headers6()

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Replace the macro SET_TCP_HEADER_COMMON_V4_V6() by a new function
tcp_fill_header().

Move IPv4 and IPv6 code from tcp_l2_buf_fill_headers() to
tcp_fill_headers4() and tcp_fill_headers6()

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-ID: <20240303135114.1023026-10-lvivier@redhat.com>
[dwg: Correct commit message with new function names]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Laurent Vivier 2024-03-06 16:58:38 +11:00 committed by Stefano Brivio
parent 6b22e10a26
commit bb11d15495
1 changed files with 106 additions and 50 deletions
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156
tcp.c
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@ -1327,6 +1327,108 @@ void tcp_defer_handler(struct ctx *c)
tcp_l2_data_buf_flush(c);
}
/**
* tcp_fill_header() - Fill the TCP header fields for a given TCP segment.
*
* @th: Pointer to the TCP header structure
* @conn: Pointer to the TCP connection structure
* @seq: Sequence number
*/
static void tcp_fill_header(struct tcphdr *th,
const struct tcp_tap_conn *conn, uint32_t seq)
{
th->source = htons(conn->fport);
th->dest = htons(conn->eport);
th->seq = htonl(seq);
th->ack_seq = htonl(conn->seq_ack_to_tap);
if (conn->events & ESTABLISHED) {
th->window = htons(conn->wnd_to_tap);
} else {
unsigned wnd = conn->wnd_to_tap << conn->ws_to_tap;
th->window = htons(MIN(wnd, USHRT_MAX));
}
}
/**
* tcp_fill_headers4() - Fill 802.3, IPv4, TCP headers in pre-cooked buffers
* @c: Execution context
* @conn: Connection pointer
* @iph: Pointer to IPv4 header
* @th: Pointer to TCP header
* @plen: Payload length (including TCP header options)
* @check: Checksum, if already known
* @seq: Sequence number for this segment
*
* Return: The total length of the IPv4 packet, host order
*/
static size_t tcp_fill_headers4(const struct ctx *c,
const struct tcp_tap_conn *conn,
struct iphdr *iph, struct tcphdr *th,
size_t plen, const uint16_t *check,
uint32_t seq)
{
size_t ip_len = plen + sizeof(struct iphdr) + sizeof(struct tcphdr);
const struct in_addr *a4 = inany_v4(&conn->faddr);
ASSERT(a4);
iph->tot_len = htons(ip_len);
iph->saddr = a4->s_addr;
iph->daddr = c->ip4.addr_seen.s_addr;
iph->check = check ? *check :
csum_ip4_header(iph->tot_len, IPPROTO_TCP,
*a4, c->ip4.addr_seen);
tcp_fill_header(th, conn, seq);
tcp_update_check_tcp4(iph, th);
return ip_len;
}
/**
* tcp_fill_headers6() - Fill 802.3, IPv6, TCP headers in pre-cooked buffers
* @c: Execution context
* @conn: Connection pointer
* @ip6h: Pointer to IPv6 header
* @th: Pointer to TCP header
* @plen: Payload length (including TCP header options)
* @check: Checksum, if already known
* @seq: Sequence number for this segment
*
* Return: The total length of the IPv6 packet, host order
*/
static size_t tcp_fill_headers6(const struct ctx *c,
const struct tcp_tap_conn *conn,
struct ipv6hdr *ip6h, struct tcphdr *th,
size_t plen, uint32_t seq)
{
size_t ip_len = plen + sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
ip6h->payload_len = htons(plen + sizeof(struct tcphdr));
ip6h->saddr = conn->faddr.a6;
if (IN6_IS_ADDR_LINKLOCAL(&ip6h->saddr))
ip6h->daddr = c->ip6.addr_ll_seen;
else
ip6h->daddr = c->ip6.addr_seen;
ip6h->hop_limit = 255;
ip6h->version = 6;
ip6h->nexthdr = IPPROTO_TCP;
ip6h->flow_lbl[0] = (conn->sock >> 16) & 0xf;
ip6h->flow_lbl[1] = (conn->sock >> 8) & 0xff;
ip6h->flow_lbl[2] = (conn->sock >> 0) & 0xff;
tcp_fill_header(th, conn, seq);
tcp_update_check_tcp6(ip6h, th);
return ip_len;
}
/**
* tcp_l2_buf_fill_headers() - Fill 802.3, IP, TCP headers in pre-cooked buffers
* @c: Execution context
@ -1346,67 +1448,21 @@ static size_t tcp_l2_buf_fill_headers(const struct ctx *c,
const struct in_addr *a4 = inany_v4(&conn->faddr);
size_t ip_len, tlen;
#define SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq) \
do { \
b->th.source = htons(conn->fport); \
b->th.dest = htons(conn->eport); \
b->th.seq = htonl(seq); \
b->th.ack_seq = htonl(conn->seq_ack_to_tap); \
if (conn->events & ESTABLISHED) { \
b->th.window = htons(conn->wnd_to_tap); \
} else { \
unsigned wnd = conn->wnd_to_tap << conn->ws_to_tap; \
\
b->th.window = htons(MIN(wnd, USHRT_MAX)); \
} \
} while (0)
if (a4) {
struct tcp4_l2_buf_t *b = (struct tcp4_l2_buf_t *)p;
ip_len = plen + sizeof(struct iphdr) + sizeof(struct tcphdr);
b->iph.tot_len = htons(ip_len);
b->iph.saddr = a4->s_addr;
b->iph.daddr = c->ip4.addr_seen.s_addr;
b->iph.check = check ? *check :
csum_ip4_header(b->iph.tot_len, IPPROTO_TCP,
*a4, c->ip4.addr_seen);
SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
tcp_update_check_tcp4(&b->iph, &b->th);
ip_len = tcp_fill_headers4(c, conn, &b->iph, &b->th, plen,
check, seq);
tlen = tap_iov_len(c, &b->taph, ip_len);
} else {
struct tcp6_l2_buf_t *b = (struct tcp6_l2_buf_t *)p;
ip_len = plen + sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
b->ip6h.payload_len = htons(plen + sizeof(struct tcphdr));
b->ip6h.saddr = conn->faddr.a6;
if (IN6_IS_ADDR_LINKLOCAL(&b->ip6h.saddr))
b->ip6h.daddr = c->ip6.addr_ll_seen;
else
b->ip6h.daddr = c->ip6.addr_seen;
memset(b->ip6h.flow_lbl, 0, 3);
SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
tcp_update_check_tcp6(&b->ip6h, &b->th);
b->ip6h.hop_limit = 255;
b->ip6h.version = 6;
b->ip6h.nexthdr = IPPROTO_TCP;
b->ip6h.flow_lbl[0] = (conn->sock >> 16) & 0xf;
b->ip6h.flow_lbl[1] = (conn->sock >> 8) & 0xff;
b->ip6h.flow_lbl[2] = (conn->sock >> 0) & 0xff;
ip_len = tcp_fill_headers6(c, conn, &b->ip6h, &b->th, plen,
seq);
tlen = tap_iov_len(c, &b->taph, ip_len);
}
#undef SET_TCP_HEADER_COMMON_V4_V6
return tlen;
}