diff options
| -rw-r--r-- | tcp.c | 156 |
1 files changed, 106 insertions, 50 deletions
@@ -1328,6 +1328,108 @@ void tcp_defer_handler(struct ctx *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 * @conn: Connection pointer @@ -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; } |