diff options
| -rw-r--r-- | trafgen/Makefile | 1 | ||||
| -rw-r--r-- | trafgen_l4.c | 71 | ||||
| -rw-r--r-- | trafgen_l4.h | 13 | ||||
| -rw-r--r-- | trafgen_proto.c | 2 |
4 files changed, 87 insertions, 0 deletions
diff --git a/trafgen/Makefile b/trafgen/Makefile index 4f342ca..3f78f07 100644 --- a/trafgen/Makefile +++ b/trafgen/Makefile @@ -22,6 +22,7 @@ trafgen-objs = xmalloc.o \ trafgen_proto.o \ trafgen_l2.o \ trafgen_l3.o \ + trafgen_l4.o \ trafgen_lexer.yy.o \ trafgen_parser.tab.o \ trafgen.o diff --git a/trafgen_l4.c b/trafgen_l4.c new file mode 100644 index 0000000..286e54a --- /dev/null +++ b/trafgen_l4.c @@ -0,0 +1,71 @@ +/* + * netsniff-ng - the packet sniffing beast + * Subject to the GPL, version 2. + */ + +#include <stdbool.h> +#include <netinet/in.h> + +#include "die.h" +#include "csum.h" +#include "built_in.h" +#include "trafgen_l3.h" +#include "trafgen_l4.h" +#include "trafgen_conf.h" +#include "trafgen_proto.h" + +static struct proto_field udp_fields[] = { + { .id = UDP_SPORT, .len = 2, .offset = 0 }, + { .id = UDP_DPORT, .len = 2, .offset = 2 }, + { .id = UDP_LEN, .len = 2, .offset = 4 }, + { .id = UDP_CSUM, .len = 2, .offset = 6 }, +}; + +static void udp_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_UDP); + + proto_header_fields_add(hdr, udp_fields, array_size(udp_fields)); +} + +static void udp_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; + + total_len = pkt->len - hdr->pkt_offset; + proto_field_set_default_be16(hdr, UDP_LEN, total_len); + + if (proto_field_is_set(hdr, UDP_CSUM)) + return; + + if (!lower || lower->id != PROTO_IP4) + return; + + total_len = proto_field_get_u16(hdr, UDP_LEN); + csum = p4_csum((void *) proto_header_ptr(lower), proto_header_ptr(hdr), + total_len, IPPROTO_UDP); + + proto_field_set_be16(hdr, UDP_CSUM, bswap_16(csum)); +} + +static struct proto_hdr udp_hdr = { + .id = PROTO_UDP, + .layer = PROTO_L4, + .header_init = udp_header_init, + .packet_finish = udp_packet_finish, +}; + +void protos_l4_init(void) +{ + proto_header_register(&udp_hdr); +} diff --git a/trafgen_l4.h b/trafgen_l4.h new file mode 100644 index 0000000..4651009 --- /dev/null +++ b/trafgen_l4.h @@ -0,0 +1,13 @@ +#ifndef TRAFGEN_L4_H +#define TRAFGEN_L4_H + +enum udp_field { + UDP_SPORT, + UDP_DPORT, + UDP_LEN, + UDP_CSUM, +}; + +extern void protos_l4_init(void); + +#endif /* TRAFGEN_L4_H */ diff --git a/trafgen_proto.c b/trafgen_proto.c index 75556f9..5fcb5cc 100644 --- a/trafgen_proto.c +++ b/trafgen_proto.c @@ -13,6 +13,7 @@ #include "trafgen_conf.h" #include "trafgen_l2.h" #include "trafgen_l3.h" +#include "trafgen_l4.h" #include "trafgen_proto.h" #define field_shift_and_mask(f, v) (((v) << (f)->shift) & \ @@ -362,6 +363,7 @@ void protos_init(const char *dev) protos_l2_init(); protos_l3_init(); + protos_l4_init(); for (p = registered; p; p = p->next) p->ctx = &ctx; |