diff options
Diffstat (limited to 'print-cdp.c')
| -rw-r--r-- | print-cdp.c | 60 |
1 files changed, 52 insertions, 8 deletions
diff --git a/print-cdp.c b/print-cdp.c index a44a28d2..b8ede526 100644 --- a/print-cdp.c +++ b/print-cdp.c @@ -26,7 +26,7 @@ #ifndef lint static const char rcsid[] = - "@(#) $Header: /tcpdump/master/tcpdump/print-cdp.c,v 1.9 2001-07-04 20:56:39 fenner Exp $"; + "@(#) $Header: /tcpdump/master/tcpdump/print-cdp.c,v 1.10 2001-08-25 09:46:33 guy Exp $"; #endif #ifdef HAVE_CONFIG_H @@ -142,13 +142,29 @@ trunc: printf("[|cdp]"); } +/* + * Protocol type values. + * + * PT_NLPID means that the protocol type field contains an OSI NLPID. + * + * PT_IEEE_802_2 means that the protocol type field contains an IEEE 802.2 + * LLC header that specifies that the payload is for that protocol. + */ +#define PT_NLPID 1 /* OSI NLPID */ +#define PT_IEEE_802_2 2 /* IEEE 802.2 LLC header */ + static int cdp_print_addr(const u_char * p, int l) { - int pl, al, num; + int pt, pl, al, num; const u_char *endp = p + l; +#ifdef INET6 + static u_char prot_ipv6[] = { + 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x86, 0xdd + }; +#endif - num = (p[0] << 24) + (p[1] << 16) + (p[2] << 8) + p[3]; + num = EXTRACT_32BITS(p); p += 4; printf(" (%d): ", num); @@ -156,20 +172,48 @@ cdp_print_addr(const u_char * p, int l) while (p < endp && num >= 0) { if (p + 2 > endp) goto trunc; - pl = p[1]; + pt = p[0]; /* type of "protocol" field */ + pl = p[1]; /* length of "protocol" field */ p += 2; - /* special case: IPv4, protocol type=0xcc, addr. length=4 */ - if (p + 3 > endp) + if (p + pl + 2 > endp) goto trunc; - if (pl == 1 && *p == 0xcc && p[1] == 0 && p[2] == 4) { + al = EXTRACT_16BITS(&p[pl]); /* address length */ + + if (pt == PT_NLPID && pl == 1 && *p == 0xcc && al == 4) { + /* + * IPv4: protocol type = NLPID, protocol length = 1 + * (1-byte NLPID), protocol = 0xcc (NLPID for IPv4), + * address length = 4 + */ p += 3; if (p + 4 > endp) goto trunc; printf("IPv4 %u.%u.%u.%u", p[0], p[1], p[2], p[3]); p += 4; - } else { /* generic case: just print raw data */ + } +#ifdef INET6 + else if (pt == PT_IEEE_802_2 && pl == 8 && + memcmp(p, prot_ipv6, 8) == 0 && al == 16) { + /* + * IPv6: protocol type = IEEE 802.2 header, + * protocol length = 8 (size of LLC+SNAP header), + * protocol = LLC+SNAP header with the IPv6 + * Ethertype, address length = 16 + */ + p += 10; + if (p + al > endp) + goto trunc; + + printf("IPv6 %s", ip6addr_string(p)); + p += al; + } +#endif + else { + /* + * Generic case: just print raw data + */ if (p + pl > endp) goto trunc; printf("pt=0x%02x, pl=%d, pb=", *(p - 2), pl); |