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/*
* netsniff-ng - the packet sniffing beast
* Subject to the GPL, version 2.
*/
#include <net/if_arp.h>
#include "die.h"
#include "dev.h"
#include "csum.h"
#include "built_in.h"
#include "trafgen_l2.h"
#include "trafgen_l3.h"
#include "trafgen_proto.h"
#include "trafgen_conf.h"
static struct proto_field ipv4_fields[] = {
{ .id = IP4_VER, .len = 1, .offset = 0, .shift = 4, .mask = 0xf0 },
{ .id = IP4_IHL, .len = 1, .offset = 0, .shift = 0, .mask = 0x0f },
{ .id = IP4_DSCP, .len = 1, .offset = 1, .shift = 2, .mask = 0xfc },
{ .id = IP4_ECN, .len = 1, .offset = 1, .shift = 0, .mask = 0x03 },
{ .id = IP4_TOS, .len = 1, .offset = 1 },
{ .id = IP4_LEN, .len = 2, .offset = 2 },
{ .id = IP4_ID, .len = 2, .offset = 4 },
{ .id = IP4_FLAGS, .len = 2, .offset = 6, .shift = 13, .mask = 0xe000 },
{ .id = IP4_MF, .len = 2, .offset = 6, .shift = 13, .mask = 0x2000 },
{ .id = IP4_DF, .len = 2, .offset = 6, .shift = 14, .mask = 0x4000 },
{ .id = IP4_FRAG_OFFS, .len = 2, .offset = 6, .shift = 0, .mask = 0x1fff },
{ .id = IP4_TTL, .len = 1, .offset = 8 },
{ .id = IP4_PROTO, .len = 1, .offset = 9 },
{ .id = IP4_CSUM, .len = 2, .offset = 10 },
{ .id = IP4_SADDR, .len = 4, .offset = 12 },
{ .id = IP4_DADDR, .len = 4, .offset = 16 },
};
static void ipv4_header_init(struct proto_hdr *hdr)
{
struct dev_io *dev = proto_dev_get();
/* In case of tun interface we do not need to create Ethernet header */
if (dev_io_is_pcap(dev) || device_type(dev_io_name_get(dev)) != ARPHRD_NONE)
proto_lower_default_add(hdr, PROTO_ETH);
proto_header_fields_add(hdr, ipv4_fields, array_size(ipv4_fields));
proto_hdr_field_set_default_u8(hdr, IP4_VER, 4);
proto_hdr_field_set_default_u8(hdr, IP4_IHL, 5);
proto_hdr_field_set_default_dev_ipv4(hdr, IP4_SADDR);
}
static void ipv4_field_changed(struct proto_field *field)
{
field->hdr->is_csum_valid = false;
if (field->id == IP4_SADDR || field->id == IP4_DADDR) {
struct proto_hdr *upper = proto_upper_header(field->hdr);
if (upper && (upper->ops->id == PROTO_UDP || upper->ops->id == PROTO_TCP))
upper->is_csum_valid = false;
}
}
static void ipv4_csum_update(struct proto_hdr *hdr)
{
struct packet *pkt;
uint16_t csum;
if (hdr->is_csum_valid)
return;
if (proto_hdr_field_is_set(hdr, IP4_CSUM))
return;
pkt = packet_get(hdr->pkt_id);
proto_hdr_field_set_default_u16(hdr, IP4_CSUM, 0);
csum = htons(calc_csum(&pkt->payload[hdr->pkt_offset], hdr->len));
proto_hdr_field_set_default_u16(hdr, IP4_CSUM, bswap_16(csum));
hdr->is_csum_valid = true;
}
static void ipv4_packet_finish(struct proto_hdr *hdr)
{
struct packet *pkt = proto_hdr_packet(hdr);
uint16_t total_len;
total_len = pkt->len - hdr->pkt_offset;
proto_hdr_field_set_default_be16(hdr, IP4_LEN, total_len);
ipv4_csum_update(hdr);
}
static void ipv4_set_next_proto(struct proto_hdr *hdr, enum proto_id pid)
{
uint8_t ip_proto;
switch (pid) {
case PROTO_IP4:
ip_proto = IPPROTO_IPIP;
break;
case PROTO_IP6:
ip_proto = IPPROTO_IPV6;
break;
case PROTO_ICMP4:
ip_proto = IPPROTO_ICMP;
break;
case PROTO_UDP:
ip_proto = IPPROTO_UDP;
break;
case PROTO_TCP:
ip_proto = IPPROTO_TCP;
break;
default:
bug();
}
proto_hdr_field_set_default_u8(hdr, IP4_PROTO, ip_proto);
}
static const struct proto_ops ipv4_proto_ops = {
.id = PROTO_IP4,
.layer = PROTO_L3,
.header_init = ipv4_header_init,
.packet_update = ipv4_csum_update,
.field_changed = ipv4_field_changed,
.packet_finish = ipv4_packet_finish,
.set_next_proto = ipv4_set_next_proto,
};
static struct proto_field ipv6_fields[] = {
{ .id = IP6_VER, .len = 4, .offset = 0, .shift = 28, .mask = 0xf0000000 },
{ .id = IP6_CLASS, .len = 4, .offset = 0, .shift = 20, .mask = 0x0ff00000 },
{ .id = IP6_FLOW_LBL, .len = 4, .offset = 0, .shift = 0, .mask = 0x000fffff },
{ .id = IP6_LEN, .len = 2, .offset = 4 },
{ .id = IP6_NEXT_HDR, .len = 1, .offset = 6 },
{ .id = IP6_HOP_LIMIT, .len = 1, .offset = 7 },
{ .id = IP6_SADDR, .len = 16, .offset = 8 },
{ .id = IP6_DADDR, .len = 16, .offset = 24 },
};
static void ipv6_header_init(struct proto_hdr *hdr)
{
struct dev_io *dev = proto_dev_get();
/* In case of tun interface we do not need to create Ethernet header */
if (dev_io_is_netdev(dev) && device_type(dev_io_name_get(dev)) != ARPHRD_NONE)
proto_lower_default_add(hdr, PROTO_ETH);
proto_header_fields_add(hdr, ipv6_fields, array_size(ipv6_fields));
proto_hdr_field_set_default_be32(hdr, IP6_VER, 6);
proto_hdr_field_set_default_dev_ipv6(hdr, IP6_SADDR);
}
static void ipv6_field_changed(struct proto_field *field)
{
if (field->id == IP6_SADDR || field->id == IP6_DADDR) {
struct proto_hdr *upper = proto_upper_header(field->hdr);
if (upper && (upper->ops->id == PROTO_UDP || upper->ops->id == PROTO_TCP))
upper->is_csum_valid = false;
}
}
#define IPV6_HDR_LEN 40
static void ipv6_packet_finish(struct proto_hdr *hdr)
{
struct packet *pkt = proto_hdr_packet(hdr);
uint16_t total_len = pkt->len - hdr->pkt_offset - IPV6_HDR_LEN;
proto_hdr_field_set_default_be16(hdr, IP6_LEN, total_len);
}
static void ipv6_set_next_proto(struct proto_hdr *hdr, enum proto_id pid)
{
uint8_t ip_proto;
switch (pid) {
case PROTO_ICMP6:
ip_proto = IPPROTO_ICMPV6;
break;
case PROTO_UDP:
ip_proto = IPPROTO_UDP;
break;
case PROTO_TCP:
ip_proto = IPPROTO_TCP;
break;
default:
bug();
}
proto_hdr_field_set_default_u8(hdr, IP6_NEXT_HDR, ip_proto);
}
static const struct proto_ops ipv6_proto_ops = {
.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,
};
void protos_l3_init(void)
{
proto_ops_register(&ipv4_proto_ops);
proto_ops_register(&ipv6_proto_ops);
}
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