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/*
* 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)
{
proto_lower_default_add(hdr, PROTO_IP4);
proto_header_fields_add(hdr, udp_fields, array_size(udp_fields));
}
static void udp_field_changed(struct proto_field *field)
{
field->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;
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->ops->id) {
case PROTO_IP4:
csum = p4_csum((void *) proto_header_ptr(lower), proto_header_ptr(hdr),
total_len, IPPROTO_UDP);
break;
case PROTO_IP6:
csum = p6_csum((void *) proto_header_ptr(lower), proto_header_ptr(hdr),
total_len, IPPROTO_UDP);
break;
default:
csum = 0;
break;
}
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 const struct proto_ops udp_proto_ops = {
.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[] = {
{ .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 tcp_header_init(struct proto_hdr *hdr)
{
proto_lower_default_add(hdr, PROTO_IP4);
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)
return;
total_len = pkt->len - hdr->pkt_offset;
switch (lower->ops->id) {
case PROTO_IP4:
csum = p4_csum((void *) proto_header_ptr(lower), proto_header_ptr(hdr),
total_len, IPPROTO_TCP);
break;
case PROTO_IP6:
csum = p6_csum((void *) proto_header_ptr(lower), proto_header_ptr(hdr),
total_len, IPPROTO_TCP);
break;
default:
csum = 0;
break;
}
proto_field_set_be16(hdr, TCP_CSUM, bswap_16(csum));
}
static const struct proto_ops tcp_proto_ops = {
.id = PROTO_TCP,
.layer = PROTO_L4,
.header_init = tcp_header_init,
.packet_finish = tcp_packet_finish,
};
static struct proto_field icmpv4_fields[] = {
{ .id = ICMPV4_TYPE, .len = 1, .offset = 0 },
{ .id = ICMPV4_CODE, .len = 1, .offset = 1 },
{ .id = ICMPV4_CSUM, .len = 2, .offset = 2 },
/* Echo/Ping fields */
{ .id = ICMPV4_ID, .len = 2, .offset = 4 },
{ .id = ICMPV4_SEQ, .len = 2, .offset = 6 },
/* Redirect field */
{ .id = ICMPV4_REDIR_ADDR, .len = 4, .offset = 4 },
/* Next-hop MTU */
{ .id = ICMPV4_MTU, .len = 2, .offset = 6 },
};
static void icmpv4_header_init(struct proto_hdr *hdr)
{
proto_lower_default_add(hdr, PROTO_IP4);
proto_header_fields_add(hdr, icmpv4_fields, array_size(icmpv4_fields));
}
static void icmpv4_csum_update(struct proto_hdr *hdr)
{
struct packet *pkt;
uint16_t csum;
if (hdr->is_csum_valid)
return;
if (proto_field_is_set(hdr, ICMPV4_CSUM))
return;
pkt = packet_get(hdr->pkt_id);
proto_field_set_default_u16(hdr, ICMPV4_CSUM, 0);
csum = htons(calc_csum(proto_header_ptr(hdr), pkt->len - hdr->pkt_offset));
proto_field_set_default_u16(hdr, ICMPV4_CSUM, bswap_16(csum));
hdr->is_csum_valid = true;
}
static void icmpv4_field_changed(struct proto_field *field)
{
field->hdr->is_csum_valid = false;
}
static const struct proto_ops icmpv4_proto_ops = {
.id = PROTO_ICMP4,
.layer = PROTO_L4,
.header_init = icmpv4_header_init,
.packet_update = icmpv4_csum_update,
.packet_finish = icmpv4_csum_update,
.field_changed = icmpv4_field_changed,
};
static struct proto_field icmpv6_fields[] = {
{ .id = ICMPV6_TYPE, .len = 1, .offset = 0 },
{ .id = ICMPV6_CODE, .len = 1, .offset = 1 },
{ .id = ICMPV6_CSUM, .len = 2, .offset = 2 }
};
static void icmpv6_header_init(struct proto_hdr *hdr)
{
proto_lower_default_add(hdr, PROTO_IP6);
proto_header_fields_add(hdr, icmpv6_fields, array_size(icmpv6_fields));
}
static void icmpv6_csum_update(struct proto_hdr *hdr)
{
struct proto_hdr *lower = proto_lower_header(hdr);
struct packet *pkt = packet_get(hdr->pkt_id);
uint16_t total_len;
uint16_t csum;
if (unlikely(!lower))
return;
if (hdr->is_csum_valid)
return;
if (proto_field_is_set(hdr, ICMPV6_CSUM))
return;
total_len = pkt->len - hdr->pkt_offset;
proto_field_set_be16(hdr, ICMPV6_CSUM, 0);
if (likely(lower->ops->id == PROTO_IP6)) {
csum = p6_csum((void *) proto_header_ptr(lower), proto_header_ptr(hdr),
total_len, IPPROTO_ICMPV6);
proto_field_set_be16(hdr, ICMPV6_CSUM, bswap_16(csum));
hdr->is_csum_valid = true;
}
}
static void icmpv6_field_changed(struct proto_field *field)
{
field->hdr->is_csum_valid = false;
}
static struct proto_ops icmpv6_proto_ops = {
.id = PROTO_ICMP6,
.layer = PROTO_L4,
.header_init = icmpv6_header_init,
.packet_finish = icmpv6_csum_update,
.packet_update = icmpv6_csum_update,
.field_changed = icmpv6_field_changed,
};
void protos_l4_init(void)
{
proto_ops_register(&udp_proto_ops);
proto_ops_register(&tcp_proto_ops);
proto_ops_register(&icmpv4_proto_ops);
proto_ops_register(&icmpv6_proto_ops);
}
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