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tcp: Merge tcp_fill_headers[46]() with each other

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We have different versions of this function for IPv4 and IPv6, but the
caller already requires some IP version specific code to get the right
header pointers.  Instead, have a common function that fills either an
IPv4 or an IPv6 header based on which header pointer it is passed.  This
allows us to remove a small amount of code duplication and make a few
slightly ugly conditionals.

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 2024-11-27 14:54:09 +11:00 committed by Stefano Brivio
parent 2abf5ab7f3
commit a6348cad51
4 changed files with 83 additions and 105 deletions
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124
tcp.c
View File

@ -877,96 +877,84 @@ static void tcp_fill_header(struct tcphdr *th,
} }
/** /**
* tcp_fill_headers4() - Fill 802.3, IPv4, TCP headers in pre-cooked buffers * tcp_fill_headers() - Fill 802.3, IP, TCP headers
* @conn: Connection pointer * @conn: Connection pointer
* @taph: tap backend specific header * @taph: tap backend specific header
* @iph: Pointer to IPv4 header * @ip4h: Pointer to IPv4 header, or NULL
* @ip6h: Pointer to IPv6 header, or NULL
* @th: Pointer to TCP header * @th: Pointer to TCP header
* @payload: TCP payload * @payload: TCP payload
* @check: Checksum, if already known * @ip4_check: IPv4 checksum, if already known
* @seq: Sequence number for this segment * @seq: Sequence number for this segment
* @no_tcp_csum: Do not set TCP checksum * @no_tcp_csum: Do not set TCP checksum
*/ */
void tcp_fill_headers4(const struct tcp_tap_conn *conn, void tcp_fill_headers(const struct tcp_tap_conn *conn,
struct tap_hdr *taph, struct iphdr *iph, struct tap_hdr *taph,
struct tcphdr *th, struct iov_tail *payload, struct iphdr *ip4h, struct ipv6hdr *ip6h,
const uint16_t *check, uint32_t seq, bool no_tcp_csum) struct tcphdr *th, struct iov_tail *payload,
const uint16_t *ip4_check, uint32_t seq, bool no_tcp_csum)
{ {
const struct flowside *tapside = TAPFLOW(conn); const struct flowside *tapside = TAPFLOW(conn);
const struct in_addr *src4 = inany_v4(&tapside->oaddr);
const struct in_addr *dst4 = inany_v4(&tapside->eaddr);
size_t l4len = iov_tail_size(payload) + sizeof(*th); size_t l4len = iov_tail_size(payload) + sizeof(*th);
size_t l3len = l4len + sizeof(*iph); size_t l3len = l4len;
uint32_t psum = 0;
ASSERT(src4 && dst4); if (ip4h) {
const struct in_addr *src4 = inany_v4(&tapside->oaddr);
const struct in_addr *dst4 = inany_v4(&tapside->eaddr);
iph->tot_len = htons(l3len); ASSERT(src4 && dst4);
iph->saddr = src4->s_addr;
iph->daddr = dst4->s_addr;
iph->check = check ? *check : l3len += + sizeof(*ip4h);
csum_ip4_header(l3len, IPPROTO_TCP, *src4, *dst4);
ip4h->tot_len = htons(l3len);
ip4h->saddr = src4->s_addr;
ip4h->daddr = dst4->s_addr;
if (ip4_check)
ip4h->check = *ip4_check;
else
ip4h->check = csum_ip4_header(l3len, IPPROTO_TCP,
*src4, *dst4);
if (!no_tcp_csum) {
psum = proto_ipv4_header_psum(l4len, IPPROTO_TCP,
*src4, *dst4);
}
}
if (ip6h) {
l3len += sizeof(*ip6h);
ip6h->payload_len = htons(l4len);
ip6h->saddr = tapside->oaddr.a6;
ip6h->daddr = tapside->eaddr.a6;
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;
if (!no_tcp_csum) {
psum = proto_ipv6_header_psum(l4len, IPPROTO_TCP,
&ip6h->saddr,
&ip6h->daddr);
}
}
tcp_fill_header(th, conn, seq); tcp_fill_header(th, conn, seq);
if (no_tcp_csum) { if (no_tcp_csum)
th->check = 0; th->check = 0;
} else { else
uint32_t psum = proto_ipv4_header_psum(l4len, IPPROTO_TCP,
*src4, *dst4);
tcp_update_csum(psum, th, payload); tcp_update_csum(psum, th, payload);
}
tap_hdr_update(taph, l3len + sizeof(struct ethhdr)); tap_hdr_update(taph, l3len + sizeof(struct ethhdr));
} }
/**
* tcp_fill_headers6() - Fill 802.3, IPv6, TCP headers in pre-cooked buffers
* @conn: Connection pointer
* @taph: tap backend specific header
* @ip6h: Pointer to IPv6 header
* @th: Pointer to TCP header
* @payload: TCP payload
* @check: Checksum, if already known
* @seq: Sequence number for this segment
* @no_tcp_csum: Do not set TCP checksum
*/
void tcp_fill_headers6(const struct tcp_tap_conn *conn,
struct tap_hdr *taph, struct ipv6hdr *ip6h,
struct tcphdr *th, struct iov_tail *payload,
uint32_t seq, bool no_tcp_csum)
{
size_t l4len = iov_tail_size(payload) + sizeof(*th);
const struct flowside *tapside = TAPFLOW(conn);
ip6h->payload_len = htons(l4len);
ip6h->saddr = tapside->oaddr.a6;
ip6h->daddr = tapside->eaddr.a6;
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);
if (no_tcp_csum) {
th->check = 0;
} else {
uint32_t psum = proto_ipv6_header_psum(l4len, IPPROTO_TCP,
&ip6h->saddr,
&ip6h->daddr);
tcp_update_csum(psum, th, payload);
}
tap_hdr_update(taph, l4len + sizeof(*ip6h) + sizeof(struct ethhdr));
}
/** /**
* tcp_update_seqack_wnd() - Update ACK sequence and window to guest/tap * tcp_update_seqack_wnd() - Update ACK sequence and window to guest/tap
* @c: Execution context * @c: Execution context

19
tcp_buf.c
View File

@ -161,18 +161,19 @@ static void tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
{ {
struct iov_tail tail = IOV_TAIL(&iov[TCP_IOV_PAYLOAD], 1, 0); struct iov_tail tail = IOV_TAIL(&iov[TCP_IOV_PAYLOAD], 1, 0);
struct tcphdr *th = IOV_REMOVE_HEADER(&tail, struct tcphdr); struct tcphdr *th = IOV_REMOVE_HEADER(&tail, struct tcphdr);
struct tap_hdr *taph = iov[TCP_IOV_TAP].iov_base;
const struct flowside *tapside = TAPFLOW(conn); const struct flowside *tapside = TAPFLOW(conn);
const struct in_addr *a4 = inany_v4(&tapside->oaddr); const struct in_addr *a4 = inany_v4(&tapside->oaddr);
struct ipv6hdr *ip6h = NULL;
struct iphdr *ip4h = NULL;
if (a4) { if (a4)
tcp_fill_headers4(conn, iov[TCP_IOV_TAP].iov_base, ip4h = iov[TCP_IOV_IP].iov_base;
iov[TCP_IOV_IP].iov_base, th, else
&tail, check, seq, no_tcp_csum); ip6h = iov[TCP_IOV_IP].iov_base;
} else {
tcp_fill_headers6(conn, iov[TCP_IOV_TAP].iov_base, tcp_fill_headers(conn, taph, ip4h, ip6h, th, &tail,
iov[TCP_IOV_IP].iov_base, th, check, seq, no_tcp_csum);
&tail, seq, no_tcp_csum);
}
} }
/** /**

13
tcp_internal.h
View File

@ -164,14 +164,11 @@ struct tcp_info_linux;
void tcp_update_csum(uint32_t psum, struct tcphdr *th, void tcp_update_csum(uint32_t psum, struct tcphdr *th,
struct iov_tail *payload); struct iov_tail *payload);
void tcp_fill_headers4(const struct tcp_tap_conn *conn, void tcp_fill_headers(const struct tcp_tap_conn *conn,
struct tap_hdr *taph, struct iphdr *iph, struct tap_hdr *taph,
struct tcphdr *th, struct iov_tail *payload, struct iphdr *ip4h, struct ipv6hdr *ip6h,
const uint16_t *check, uint32_t seq, bool no_tcp_csum); struct tcphdr *th, struct iov_tail *payload,
void tcp_fill_headers6(const struct tcp_tap_conn *conn, const uint16_t *ip4_check, uint32_t seq, bool no_tcp_csum);
struct tap_hdr *taph, struct ipv6hdr *ip6h,
struct tcphdr *th, struct iov_tail *payload,
uint32_t seq, bool no_tcp_csum);
int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn, int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
bool force_seq, struct tcp_info_linux *tinfo); bool force_seq, struct tcp_info_linux *tinfo);

32
tcp_vu.c
View File

@ -111,9 +111,9 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
size_t optlen, hdrlen; size_t optlen, hdrlen;
struct vu_virtq_element flags_elem[2]; struct vu_virtq_element flags_elem[2];
struct ipv6hdr *ip6h = NULL; struct ipv6hdr *ip6h = NULL;
struct iphdr *ip4h = NULL;
struct iovec flags_iov[2]; struct iovec flags_iov[2];
struct tcp_syn_opts *opts; struct tcp_syn_opts *opts;
struct iphdr *iph = NULL;
struct iov_tail payload; struct iov_tail payload;
struct tcphdr *th; struct tcphdr *th;
struct ethhdr *eh; struct ethhdr *eh;
@ -144,8 +144,8 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
if (CONN_V4(conn)) { if (CONN_V4(conn)) {
eh->h_proto = htons(ETH_P_IP); eh->h_proto = htons(ETH_P_IP);
iph = vu_ip(flags_elem[0].in_sg[0].iov_base); ip4h = vu_ip(flags_elem[0].in_sg[0].iov_base);
*iph = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP); *ip4h = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
th = vu_payloadv4(flags_elem[0].in_sg[0].iov_base); th = vu_payloadv4(flags_elem[0].in_sg[0].iov_base);
} else { } else {
@ -171,12 +171,8 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
flags_elem[0].in_sg[0].iov_len = hdrlen + optlen; flags_elem[0].in_sg[0].iov_len = hdrlen + optlen;
payload = IOV_TAIL(flags_elem[0].in_sg, 1, hdrlen); payload = IOV_TAIL(flags_elem[0].in_sg, 1, hdrlen);
if (CONN_V4(conn)) { tcp_fill_headers(conn, NULL, ip4h, ip6h, th, &payload,
tcp_fill_headers4(conn, NULL, iph, th, &payload, NULL, seq, true);
NULL, seq, true);
} else {
tcp_fill_headers6(conn, NULL, ip6h, th, &payload, seq, true);
}
if (*c->pcap) { if (*c->pcap) {
tcp_vu_update_check(tapside, &flags_elem[0].in_sg[0], 1); tcp_vu_update_check(tapside, &flags_elem[0].in_sg[0], 1);
@ -339,7 +335,7 @@ static void tcp_vu_prepare(const struct ctx *c, struct tcp_tap_conn *conn,
struct iov_tail payload = IOV_TAIL(iov, iov_cnt, hdrlen); struct iov_tail payload = IOV_TAIL(iov, iov_cnt, hdrlen);
char *base = iov[0].iov_base; char *base = iov[0].iov_base;
struct ipv6hdr *ip6h = NULL; struct ipv6hdr *ip6h = NULL;
struct iphdr *iph = NULL; struct iphdr *ip4h = NULL;
struct tcphdr *th; struct tcphdr *th;
struct ethhdr *eh; struct ethhdr *eh;
@ -358,8 +354,8 @@ static void tcp_vu_prepare(const struct ctx *c, struct tcp_tap_conn *conn,
if (!v6) { if (!v6) {
eh->h_proto = htons(ETH_P_IP); eh->h_proto = htons(ETH_P_IP);
iph = vu_ip(base); ip4h = vu_ip(base);
*iph = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP); *ip4h = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
th = vu_payloadv4(base); th = vu_payloadv4(base);
} else { } else {
eh->h_proto = htons(ETH_P_IPV6); eh->h_proto = htons(ETH_P_IPV6);
@ -374,14 +370,10 @@ static void tcp_vu_prepare(const struct ctx *c, struct tcp_tap_conn *conn,
th->doff = sizeof(*th) / 4; th->doff = sizeof(*th) / 4;
th->ack = 1; th->ack = 1;
if (!v6) { tcp_fill_headers(conn, NULL, ip4h, ip6h, th, &payload,
tcp_fill_headers4(conn, NULL, iph, th, &payload, *check, conn->seq_to_tap, true);
*check, conn->seq_to_tap, true); if (ip4h)
*check = &iph->check; *check = &ip4h->check;
} else {
tcp_fill_headers6(conn, NULL, ip6h, th, &payload,
conn->seq_to_tap, true);
}
} }
/** /**