Update UDP csum field at runtime if: 1) UDP field was changed.
2) IPv4/6 source/destination addresses were changed (which is a part of UDP pseudo header), this is handled by IPv4/6 protocols. Also changed proto_lower_header(...) function to use header index to lookup lower header faster, the reason is that this function is used for updating UDP csum. Signed-off-by: Vadim Kochan <vadi...@gmail.com> --- trafgen_l3.c | 18 ++++++++++++++++++ trafgen_l4.c | 37 +++++++++++++++++++++++++++++-------- trafgen_proto.c | 36 +++++++++++++++++++++++------------- trafgen_proto.h | 2 ++ 4 files changed, 72 insertions(+), 21 deletions(-) diff --git a/trafgen_l3.c b/trafgen_l3.c index aaca5a9..dbfb1fe 100644 --- a/trafgen_l3.c +++ b/trafgen_l3.c @@ -46,6 +46,13 @@ static void ipv4_header_init(struct proto_hdr *hdr) static void ipv4_field_changed(struct proto_hdr *hdr, struct proto_field *field) { hdr->is_csum_valid = false; + + if (field->id == IP4_SADDR || field->id == IP4_DADDR) { + struct proto_hdr *upper = proto_upper_header(hdr); + + if (upper && upper->id == PROTO_UDP) + upper->is_csum_valid = false; + } } static void ipv4_csum_update(struct proto_hdr *hdr) @@ -136,6 +143,16 @@ static void ipv6_header_init(struct proto_hdr *hdr) proto_field_set_default_dev_ipv6(hdr, IP6_SADDR); } +static void ipv6_field_changed(struct proto_hdr *hdr, struct proto_field *field) +{ + if (field->id == IP6_SADDR || field->id == IP6_DADDR) { + struct proto_hdr *upper = proto_upper_header(hdr); + + if (upper && upper->id == PROTO_UDP) + upper->is_csum_valid = false; + } +} + #define IPV6_HDR_LEN 40 static void ipv6_packet_finish(struct proto_hdr *hdr) @@ -171,6 +188,7 @@ static struct proto_hdr ipv6_hdr = { .id = PROTO_IP6, .layer = PROTO_L3, .header_init = ipv6_header_init, + .field_changed = ipv6_field_changed, .packet_finish = ipv6_packet_finish, .set_next_proto = ipv6_set_next_proto, }; diff --git a/trafgen_l4.c b/trafgen_l4.c index 908641c..5749a82 100644 --- a/trafgen_l4.c +++ b/trafgen_l4.c @@ -28,22 +28,29 @@ static void udp_header_init(struct proto_hdr *hdr) proto_header_fields_add(hdr, udp_fields, array_size(udp_fields)); } -static void udp_packet_finish(struct proto_hdr *hdr) +static void udp_field_changed(struct proto_hdr *hdr, struct proto_field *field) { - struct proto_hdr *lower = proto_lower_header(hdr); - struct packet *pkt = current_packet(); + hdr->is_csum_valid = false; +} + +static void udp_csum_update(struct proto_hdr *hdr) +{ + struct proto_hdr *lower; 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 (hdr->is_csum_valid) + return; if (proto_field_is_set(hdr, UDP_CSUM)) return; - + lower = proto_lower_header(hdr); if (!lower) return; + total_len = packet_get(hdr->pkt_id)->len - hdr->pkt_offset; + + proto_field_set_default_be16(hdr, UDP_CSUM, 0); + switch (lower->id) { case PROTO_IP4: csum = p4_csum((void *) proto_header_ptr(lower), proto_header_ptr(hdr), @@ -58,14 +65,28 @@ static void udp_packet_finish(struct proto_hdr *hdr) break; } - proto_field_set_be16(hdr, UDP_CSUM, bswap_16(csum)); + proto_field_set_default_be16(hdr, UDP_CSUM, bswap_16(csum)); + hdr->is_csum_valid = true; +} + +static void udp_packet_finish(struct proto_hdr *hdr) +{ + struct packet *pkt = current_packet(); + uint16_t total_len; + + total_len = pkt->len - hdr->pkt_offset; + proto_field_set_default_be16(hdr, UDP_LEN, total_len); + + udp_csum_update(hdr); } static struct proto_hdr udp_hdr = { .id = PROTO_UDP, .layer = PROTO_L4, .header_init = udp_header_init, + .packet_update = udp_csum_update, .packet_finish = udp_packet_finish, + .field_changed = udp_field_changed, }; static struct proto_field tcp_fields[] = { diff --git a/trafgen_proto.c b/trafgen_proto.c index f57d390..9a26f04 100644 --- a/trafgen_proto.c +++ b/trafgen_proto.c @@ -39,20 +39,25 @@ static inline struct proto_hdr *proto_current_header(void) struct proto_hdr *proto_lower_header(struct proto_hdr *hdr) { - struct proto_hdr **headers = ¤t_packet()->headers[0]; - size_t headers_count = current_packet()->headers_count; - struct proto_hdr *lower = NULL; - size_t i; + struct packet *pkt = packet_get(hdr->pkt_id); + struct proto_hdr **headers = &pkt->headers[0]; - if (headers_count == 0) + if (hdr->index == 0) return NULL; - for (i = 1, lower = headers[0]; i < headers_count; i++) { - if (headers[i] == hdr) - return headers[i - 1]; - } + return headers[hdr->index - 1]; +} + +struct proto_hdr *proto_upper_header(struct proto_hdr *hdr) +{ + struct packet *pkt = packet_get(hdr->pkt_id); + struct proto_hdr **headers = &pkt->headers[0]; + size_t headers_count = pkt->headers_count; + + if (hdr->index == headers_count - 1) + return NULL; - return lower; + return headers[hdr->index + 1]; } uint8_t *proto_header_ptr(struct proto_hdr *hdr) @@ -130,11 +135,12 @@ bool proto_field_is_set(struct proto_hdr *hdr, uint32_t fid) struct proto_hdr *proto_header_init(enum proto_id pid) { - struct proto_hdr **headers = ¤t_packet()->headers[0]; + struct packet *pkt = current_packet(); + struct proto_hdr **headers = &pkt->headers[0]; struct proto_hdr *hdr = proto_header_by_id(pid); struct proto_hdr *new_hdr; - bug_on(current_packet()->headers_count >= PROTO_MAX_LAYERS); + bug_on(pkt->headers_count >= PROTO_MAX_LAYERS); new_hdr = xmalloc(sizeof(*new_hdr)); memcpy(new_hdr, hdr, sizeof(*new_hdr)); @@ -144,7 +150,11 @@ struct proto_hdr *proto_header_init(enum proto_id pid) if (new_hdr->header_init) new_hdr->header_init(new_hdr); - headers[current_packet()->headers_count++] = new_hdr; + /* This is very important to have it after header_init as + * pkt->headers_count might be changed by adding default lower headers */ + new_hdr->index = pkt->headers_count; + + headers[pkt->headers_count++] = new_hdr; return new_hdr; } diff --git a/trafgen_proto.h b/trafgen_proto.h index eb11896..dd3d0e8 100644 --- a/trafgen_proto.h +++ b/trafgen_proto.h @@ -68,6 +68,7 @@ struct proto_field { struct proto_hdr { enum proto_id id; enum proto_layer layer; + uint32_t index; struct proto_hdr *next; struct proto_ctx *ctx; @@ -99,6 +100,7 @@ extern struct proto_hdr *proto_lower_default_add(struct proto_hdr *hdr, enum proto_id pid); extern struct proto_hdr *proto_lower_header(struct proto_hdr *hdr); +extern struct proto_hdr *proto_upper_header(struct proto_hdr *hdr); extern uint8_t *proto_header_ptr(struct proto_hdr *hdr); extern void proto_header_fields_add(struct proto_hdr *hdr, -- 2.6.3 -- You received this message because you are subscribed to the Google Groups "netsniff-ng" group. 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