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/*
* netsniff-ng - the packet sniffing beast
* Copyright (C) 2009, 2010 Daniel Borkmann
* Copyright (C) 2012 Christoph Jaeger <christoph@netsniff-ng.org>
* Subject to the GPL, version 2.
*/
#include <stdio.h>
#include <stdint.h>
#include <netinet/in.h> /* for ntohs() */
#include <arpa/inet.h> /* for inet_ntop() */
#include "proto.h"
#include "csum.h"
#include "dissector_eth.h"
#include "ipv4.h"
#include "geoip.h"
#include "pkt_buff.h"
#include "built_in.h"
#define FRAG_OFF_RESERVED_FLAG(x) ((x) & 0x8000)
#define FRAG_OFF_NO_FRAGMENT_FLAG(x) ((x) & 0x4000)
#define FRAG_OFF_MORE_FRAGMENT_FLAG(x) ((x) & 0x2000)
#define FRAG_OFF_FRAGMENT_OFFSET(x) ((x) & 0x1fff)
/* IP Option Numbers (http://www.iana.org/assignments/ip-parameters) */
#define IP_OPT_EOOL 0x00
#define IP_OPT_NOP 0x01
#define IP_OPT_COPIED_FLAG(x) ((x) & 0x80)
#define IP_OPT_CLASS(x) (((x) & 0x60) >> 5)
#define IP_OPT_NUMBER(x) ((x) & 0x1F)
static void ipv4(struct pkt_buff *pkt)
{
uint16_t csum, frag_off, h_tot_len;
char src_ip[INET_ADDRSTRLEN];
char dst_ip[INET_ADDRSTRLEN];
struct ipv4hdr *ip = (struct ipv4hdr *) pkt_pull(pkt, sizeof(*ip));
uint8_t *opt, *trailer;
unsigned int trailer_len = 0;
ssize_t opts_len, opt_len;
const char *country;
char *city, *region;
if (!ip)
return;
frag_off = ntohs(ip->h_frag_off);
h_tot_len = ntohs(ip->h_tot_len);
csum = calc_csum(ip, ip->h_ihl * 4);
inet_ntop(AF_INET, &ip->h_saddr, src_ip, sizeof(src_ip));
inet_ntop(AF_INET, &ip->h_daddr, dst_ip, sizeof(dst_ip));
if ((pkt_len(pkt) + sizeof(*ip)) > h_tot_len) {
trailer_len = pkt_len(pkt) + sizeof(*ip) - h_tot_len;
trailer = pkt->data + h_tot_len + trailer_len;
}
if (trailer_len) {
tprintf(" [ Eth trailer ");
while (trailer_len--) {
tprintf("%x", *(trailer - trailer_len));
}
tprintf(" ]\n");
}
tprintf(" [ IPv4 ");
tprintf("Addr (%s => %s), ", src_ip, dst_ip);
tprintf("Proto (%u), ", ip->h_protocol);
tprintf("TTL (%u), ", ip->h_ttl);
tprintf("TOS (%u), ", ip->h_tos);
tprintf("Ver (%u), ", ip->h_version);
tprintf("IHL (%u), ", ip->h_ihl);
tprintf("Tlen (%u), ", ntohs(ip->h_tot_len));
tprintf("ID (%u), ", ntohs(ip->h_id));
tprintf("Res (%u), NoFrag (%u), MoreFrag (%u), FragOff (%u), ",
FRAG_OFF_RESERVED_FLAG(frag_off) ? 1 : 0,
FRAG_OFF_NO_FRAGMENT_FLAG(frag_off) ? 1 : 0,
FRAG_OFF_MORE_FRAGMENT_FLAG(frag_off) ? 1 : 0,
FRAG_OFF_FRAGMENT_OFFSET(frag_off));
tprintf("CSum (0x%.4x) is %s", ntohs(ip->h_check),
csum ? colorize_start_full(black, red) "bogus (!)"
colorize_end() : "ok");
if (csum)
tprintf("%s should be 0x%.4x%s", colorize_start_full(black, red),
csum_expected(ip->h_check, csum), colorize_end());
tprintf(" ]\n");
if (geoip_working()) {
struct sockaddr_in sas, sad;
memset(&sas, 0, sizeof(sas));
sas.sin_family = PF_INET;
sas.sin_addr.s_addr = ip->h_saddr;
memset(&sad, 0, sizeof(sad));
sad.sin_family = PF_INET;
sad.sin_addr.s_addr = ip->h_daddr;
tprintf("\t[ Geo (");
if ((country = geoip4_country_name(&sas))) {
tprintf("%s", country);
if ((region = geoip4_region_name(&sas))) {
tprintf(" / %s", region);
xfree(region);
}
if ((city = geoip4_city_name(&sas))) {
tprintf(" / %s", city);
xfree(city);
}
} else {
tprintf("local");
}
tprintf(" => ");
if ((country = geoip4_country_name(&sad))) {
tprintf("%s", country);
if ((region = geoip4_region_name(&sad))) {
tprintf(" / %s", region);
xfree(region);
}
if ((city = geoip4_city_name(&sad))) {
tprintf(" / %s", city);
xfree(city);
}
} else {
tprintf("local");
}
tprintf(") ]\n");
}
opts_len = max_t(uint8_t, ip->h_ihl, sizeof(*ip) / sizeof(uint32_t)) *
sizeof(uint32_t) - sizeof(*ip);
for (opt = pkt_pull(pkt, opts_len); opt && opts_len > 0; opt++) {
tprintf(" [ Option Copied (%u), Class (%u), Number (%u)",
IP_OPT_COPIED_FLAG(*opt) ? 1 : 0, IP_OPT_CLASS(*opt),
IP_OPT_NUMBER(*opt));
switch (*opt) {
case IP_OPT_EOOL:
case IP_OPT_NOP:
tprintf(" ]\n");
opts_len--;
break;
default:
/*
* Assuming that EOOL and NOP are the only single-byte
* options, treat all other options as variable in
* length with a minimum of 2.
*
* TODO: option length might be incorrect in malformed packets,
* check and handle that
*/
opt_len = *(++opt);
if (opt_len > opts_len) {
tprintf(", Len (%zd, invalid) ]\n", opt_len);
goto out;
} else
tprintf(", Len (%zd) ]\n", opt_len);
opts_len -= opt_len;
tprintf(" [ Data hex ");
for (opt_len -= 2; opt_len > 0; opt_len--)
tprintf(" %.2x", *(++opt));
tprintf(" ]\n");
break;
}
}
out:
/* cut off everything that is not part of IPv4 payload */
/* XXX there could still be an Ethernet trailer included or others */
pkt_trim(pkt, pkt_len(pkt) - min(pkt_len(pkt),
(ntohs(ip->h_tot_len) - ip->h_ihl * sizeof(uint32_t))));
pkt_set_dissector(pkt, ð_lay3, ip->h_protocol);
}
static void ipv4_less(struct pkt_buff *pkt)
{
char src_ip[INET_ADDRSTRLEN];
char dst_ip[INET_ADDRSTRLEN];
struct ipv4hdr *ip = (struct ipv4hdr *) pkt_pull(pkt, sizeof(*ip));
if (!ip)
return;
inet_ntop(AF_INET, &ip->h_saddr, src_ip, sizeof(src_ip));
inet_ntop(AF_INET, &ip->h_daddr, dst_ip, sizeof(dst_ip));
tprintf(" %s/%s Len %u", src_ip, dst_ip,
ntohs(ip->h_tot_len));
/* cut off IP options and everything that is not part of IPv4 payload */
pkt_pull(pkt, max_t(uint8_t, ip->h_ihl, sizeof(*ip) / sizeof(uint32_t))
* sizeof(uint32_t) - sizeof(*ip));
/* XXX there could still be an Ethernet trailer included or others */
#if 0
pkt_trim(pkt, pkt_len(pkt) - min(pkt_len(pkt),
(ntohs(ip->h_tot_len) - ip->h_ihl * sizeof(uint32_t))));
#endif
pkt_set_dissector(pkt, ð_lay3, ip->h_protocol);
}
struct protocol ipv4_ops = {
.key = 0x0800,
.print_full = ipv4,
.print_less = ipv4_less,
};
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