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wild stab at supporting PPP ('Linux cooked capture') packets..

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This commit is contained in:
Arnout Engelen
2004-09-02 16:10:25 +00:00
parent 19f633f2d4
commit 8697bf01a1
5 changed files with 71 additions and 36 deletions
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66
packet.cpp
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@@ -80,6 +80,21 @@ void getLocal (const char *device)
typedef u_int32_t tcp_seq;
/* ppp header, i hope ;) */
/* glanced from ethereal, it's 16 bytes, and the payload packet type is
* in the last 2 bytes... */
struct ppp_header {
u_int16_t dummy1;
u_int16_t dummy2;
u_int16_t dummy3;
u_int16_t dummy4;
u_int16_t dummy5;
u_int16_t dummy6;
u_int16_t dummy7;
u_int16_t packettype;
};
/* TCP header */
// TODO take from elsewhere.
struct tcp_hdr {
@@ -109,17 +124,33 @@ struct tcp_hdr {
u_short th_sum; /* checksum */
u_short th_urp; /* urgent pointer */
};
/* Packet 'Constructor' - but returns NULL on failure */
Packet * getPacket (const struct pcap_pkthdr * header, const u_char * packet)
Packet * getPacket (const struct pcap_pkthdr * header, const u_char * packet, packet_type headertype)
{
// const struct ethernet_hdr * ethernet = (struct ethernet_hdr *)packet;
const struct ether_header * ethernet = (struct ether_header *)packet;
/* this is the opposite endianness from http://www.iana.org/assignments/ethernet-numbers
* TODO probably have to look at network/host byte order and endianness!! */
if (ethernet->ether_type == 0x0008)
int packettype;
int headersize;
switch (headertype)
{
const struct ip * ip = (struct ip *)(packet + sizeof(ether_header));
case (packet_ethernet):
{
const struct ether_header * ethernet = (struct ether_header *)packet;
/* this is the opposite endianness from http://www.iana.org/assignments/ethernet-numbers
* TODO probably have to look at network/host byte order and endianness!! */
packettype = ethernet->ether_type;
headersize = sizeof (struct ether_header);
}; break;
case (packet_ppp):
{
const struct ppp_header * ppp = (struct ppp_header *)packet;
packettype = ppp->packettype;
headersize = sizeof (struct ether_header);
break;
}; break;
}
if (packettype == 0x0008)
{
const struct ip * ip = (struct ip *)(packet + headersize);
if (ip->ip_p != 6)
{
#if DEBUG
@@ -127,10 +158,10 @@ Packet * getPacket (const struct pcap_pkthdr * header, const u_char * packet)
#endif
return NULL;
}
const struct tcp_hdr * tcp = (struct tcp_hdr *)(packet + sizeof(ether_header) + sizeof(struct ip));
const struct tcp_hdr * tcp = (struct tcp_hdr *)(packet + headersize + sizeof(struct ip));
return new Packet (ip->ip_src, ntohs(tcp->th_sport), ip->ip_dst, ntohs(tcp->th_dport), header->len, header->ts);
} else if (ethernet->ether_type == 0xDD86) {
const struct ip6_hdr * ip6 = (struct ip6_hdr *)(packet + sizeof(ether_header));
} else if (packettype == 0xDD86) {
const struct ip6_hdr * ip6 = (struct ip6_hdr *)(packet + headersize);
if ((ip6->ip6_ctlun).ip6_un1.ip6_un1_nxt != 0x06)
{
// TODO maybe we need to skip over some headers?
@@ -139,17 +170,14 @@ Packet * getPacket (const struct pcap_pkthdr * header, const u_char * packet)
#endif
return NULL;
}
const struct tcp_hdr * tcp = (struct tcp_hdr *)(packet + sizeof(ether_header) + sizeof(ip6_hdr));
const struct tcp_hdr * tcp = (struct tcp_hdr *)(packet + headersize + sizeof(ip6_hdr));
// TODO make a Packet constructor that properly understands IPv6
//return new Packet (*((in_addr*)(&(ip6->ip6_src))), ntohs(tcp->th_sport),
// *((in_addr*)(&(ip6->ip6_dst))), ntohs(tcp->th_dport), header->len, header->ts);
return new Packet (ip6->ip6_src, ntohs(tcp->th_sport),
ip6->ip6_dst, ntohs(tcp->th_dport), header->len, header->ts);
}
#if DEBUG
std::cerr << "Dropped non-ip packet of type " << ethernet->ether_type << std::endl;
std::cerr << "Dropped non-ip packet of type " << packettype << std::endl;
#endif
return NULL;
}
@@ -246,13 +274,9 @@ char * Packet::gethashstring ()
if (sa_family == AF_INET) {
inet_ntop(sa_family, &sip, local_string, 49);
inet_ntop(sa_family, &dip, remote_string, 49);
if (DEBUG)
fprintf(stderr, "Generating IPv4 string: ");
} else {
inet_ntop(sa_family, &sip6, local_string, 49);
inet_ntop(sa_family, &dip6, remote_string, 49);
if (DEBUG)
fprintf(stderr, "Generating IPv6 string: ");
}
if (Outgoing()) {
snprintf(retval, HASHKEYSIZE * sizeof(char), "%s:%d-%s:%d", local_string, sport, remote_string, dport);
@@ -261,8 +285,6 @@ char * Packet::gethashstring ()
}
free (local_string);
free (remote_string);
if (DEBUG)
std::cout << retval << std::endl;
return retval;
}