diff options
Diffstat (limited to 'trafgen_l4.c')
| -rw-r--r-- | trafgen_l4.c | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/trafgen_l4.c b/trafgen_l4.c index 286e54a..7f80e74 100644 --- a/trafgen_l4.c +++ b/trafgen_l4.c @@ -21,6 +21,26 @@ static struct proto_field udp_fields[] = { { .id = UDP_CSUM, .len = 2, .offset = 6 }, }; +static struct proto_field tcp_fields[] = { + { .id = TCP_SPORT, .len = 2, .offset = 0 }, + { .id = TCP_DPORT, .len = 2, .offset = 2 }, + { .id = TCP_SEQ, .len = 4, .offset = 4 }, + { .id = TCP_ACK_SEQ, .len = 4, .offset = 8 }, + { .id = TCP_DOFF, .len = 2, .offset = 12, .shift = 12, .mask = 0xf000 }, + /* reserved (4 bits) */ + { .id = TCP_CWR, .len = 2, .offset = 12, .shift = 7, .mask = 0x0080 }, + { .id = TCP_ECE, .len = 2, .offset = 12, .shift = 6, .mask = 0x0040 }, + { .id = TCP_URG, .len = 2, .offset = 12, .shift = 5, .mask = 0x0020 }, + { .id = TCP_ACK, .len = 2, .offset = 12, .shift = 4, .mask = 0x0010 }, + { .id = TCP_PSH, .len = 2, .offset = 12, .shift = 3, .mask = 0x0008 }, + { .id = TCP_RST, .len = 2, .offset = 12, .shift = 2, .mask = 0x0004 }, + { .id = TCP_SYN, .len = 2, .offset = 12, .shift = 1, .mask = 0x0002 }, + { .id = TCP_FIN, .len = 2, .offset = 12, .shift = 0, .mask = 0x0001 }, + { .id = TCP_WINDOW, .len = 2, .offset = 14 }, + { .id = TCP_CSUM, .len = 2, .offset = 16 }, + { .id = TCP_URG_PTR, .len = 2, .offset = 18 }, +}; + static void udp_header_init(struct proto_hdr *hdr) { struct proto_hdr *lower; @@ -65,7 +85,51 @@ static struct proto_hdr udp_hdr = { .packet_finish = udp_packet_finish, }; +static void tcp_header_init(struct proto_hdr *hdr) +{ + struct proto_hdr *lower; + + proto_lower_default_add(PROTO_IP4); + + lower = proto_current_header(); + + if (lower->id == PROTO_IP4) + proto_field_set_default_u8(lower, IP4_PROTO, IPPROTO_TCP); + + proto_header_fields_add(hdr, tcp_fields, array_size(tcp_fields)); + + proto_field_set_default_be16(hdr, TCP_DOFF, 5); +} + +static void tcp_packet_finish(struct proto_hdr *hdr) +{ + struct proto_hdr *lower = proto_lower_header(hdr); + struct packet *pkt = current_packet(); + uint16_t total_len; + uint16_t csum; + + if (proto_field_is_set(hdr, TCP_CSUM)) + return; + + if (!lower || lower->id != PROTO_IP4) + return; + + total_len = pkt->len - hdr->pkt_offset; + csum = p4_csum((void *) proto_header_ptr(lower), proto_header_ptr(hdr), + total_len, IPPROTO_TCP); + + proto_field_set_be16(hdr, TCP_CSUM, bswap_16(csum)); +} + +static struct proto_hdr tcp_hdr = { + .id = PROTO_TCP, + .layer = PROTO_L4, + .header_init = tcp_header_init, + .packet_finish = tcp_packet_finish, +}; + void protos_l4_init(void) { proto_header_register(&udp_hdr); + proto_header_register(&tcp_hdr); } |