#define BGP_OPT_SIZE 2 /* some compilers may pad to 4 bytes */
#define BGP_CAP_HEADER_SIZE 2 /* some compilers may pad to 4 bytes */
-#define BGP_UPDATE_MINSIZE 23
-
struct bgp_notification {
u_int8_t bgpn_marker[16];
u_int16_t bgpn_len;
}; /* EXTRACT_16BITS(&bgp_route_refresh->afi) (sigh) */
#define BGP_ROUTE_REFRESH_SIZE 23
-struct bgp_attr {
- u_int8_t bgpa_flags;
- u_int8_t bgpa_type;
- union {
- u_int8_t len;
- u_int16_t elen;
- } bgpa_len;
-#define bgp_attr_len(p) \
- (((p)->bgpa_flags & 0x10) ? \
- EXTRACT_16BITS(&(p)->bgpa_len.elen) : (p)->bgpa_len.len)
-#define bgp_attr_off(p) \
- (((p)->bgpa_flags & 0x10) ? 4 : 3)
-};
+#define bgp_attr_lenlen(flags, p) \
+ (((flags) & 0x10) ? 2 : 1)
+#define bgp_attr_len(flags, p) \
+ (((flags) & 0x10) ? EXTRACT_16BITS(p) : *(p))
#define BGPTYPE_ORIGIN 1
#define BGPTYPE_AS_PATH 2
return str;
}
+#define ITEMCHECK(minlen) if (itemlen < minlen) goto badtlv;
+
int
-decode_prefix4(const u_char *pptr, char *buf, u_int buflen)
+decode_prefix4(const u_char *pptr, u_int itemlen, char *buf, u_int buflen)
{
struct in_addr addr;
- u_int plen;
+ u_int plen, plenbytes;
TCHECK(pptr[0]);
+ ITEMCHECK(1);
plen = pptr[0];
if (32 < plen)
return -1;
+ itemlen -= 1;
memset(&addr, 0, sizeof(addr));
- TCHECK2(pptr[1], (plen + 7) / 8);
- memcpy(&addr, &pptr[1], (plen + 7) / 8);
+ plenbytes = (plen + 7) / 8;
+ TCHECK2(pptr[1], plenbytes);
+ ITEMCHECK(plenbytes);
+ memcpy(&addr, &pptr[1], plenbytes);
if (plen % 8) {
- ((u_char *)&addr)[(plen + 7) / 8 - 1] &=
+ ((u_char *)&addr)[plenbytes - 1] &=
((0xff00 >> (plen % 8)) & 0xff);
}
snprintf(buf, buflen, "%s/%d", getname((u_char *)&addr), plen);
- return 1 + (plen + 7) / 8;
+ return 1 + plenbytes;
trunc:
return -2;
+
+badtlv:
+ return -3;
}
static int
-decode_labeled_prefix4(const u_char *pptr, char *buf, u_int buflen)
+decode_labeled_prefix4(const u_char *pptr, u_int itemlen, char *buf, u_int buflen)
{
struct in_addr addr;
- u_int plen;
+ u_int plen, plenbytes;
- TCHECK(pptr[0]);
+ /* prefix length and label = 4 bytes */
+ TCHECK2(pptr[0], 4);
+ ITEMCHECK(4);
plen = pptr[0]; /* get prefix length */
/* this is one of the weirdnesses of rfc3107
if (32 < plen)
return -1;
+ itemlen -= 4;
memset(&addr, 0, sizeof(addr));
- TCHECK2(pptr[4], (plen + 7) / 8);
- memcpy(&addr, &pptr[4], (plen + 7) / 8);
+ plenbytes = (plen + 7) / 8;
+ TCHECK2(pptr[4], plenbytes);
+ ITEMCHECK(plenbytes);
+ memcpy(&addr, &pptr[4], plenbytes);
if (plen % 8) {
- ((u_char *)&addr)[(plen + 7) / 8 - 1] &=
+ ((u_char *)&addr)[plenbytes - 1] &=
((0xff00 >> (plen % 8)) & 0xff);
}
/* the label may get offsetted by 4 bits so lets shift it right */
EXTRACT_24BITS(pptr+1)>>4,
((pptr[3]&1)==0) ? "(BOGUS: Bottom of Stack NOT set!)" : "(bottom)" );
- return 4 + (plen + 7) / 8;
+ return 4 + plenbytes;
trunc:
return -2;
+
+badtlv:
+ return -3;
}
/*
#ifdef INET6
int
-decode_prefix6(const u_char *pd, char *buf, u_int buflen)
+decode_prefix6(const u_char *pd, u_int itemlen, char *buf, u_int buflen)
{
struct in6_addr addr;
- u_int plen;
+ u_int plen, plenbytes;
TCHECK(pd[0]);
+ ITEMCHECK(1);
plen = pd[0];
if (128 < plen)
return -1;
+ itemlen -= 1;
memset(&addr, 0, sizeof(addr));
- TCHECK2(pd[1], (plen + 7) / 8);
- memcpy(&addr, &pd[1], (plen + 7) / 8);
+ plenbytes = (plen + 7) / 8;
+ TCHECK2(pd[1], plenbytes);
+ ITEMCHECK(plenbytes);
+ memcpy(&addr, &pd[1], plenbytes);
if (plen % 8) {
- addr.s6_addr[(plen + 7) / 8 - 1] &=
+ addr.s6_addr[plenbytes - 1] &=
((0xff00 >> (plen % 8)) & 0xff);
}
snprintf(buf, buflen, "%s/%d", getname6((u_char *)&addr), plen);
- return 1 + (plen + 7) / 8;
+ return 1 + plenbytes;
trunc:
return -2;
+
+badtlv:
+ return -3;
}
static int
-decode_labeled_prefix6(const u_char *pptr, char *buf, u_int buflen)
+decode_labeled_prefix6(const u_char *pptr, u_int itemlen, char *buf, u_int buflen)
{
struct in6_addr addr;
- u_int plen;
+ u_int plen, plenbytes;
- TCHECK(pptr[0]);
+ /* prefix length and label = 4 bytes */
+ TCHECK2(pptr[0], 4);
+ ITEMCHECK(4);
plen = pptr[0]; /* get prefix length */
if (24 > plen)
if (128 < plen)
return -1;
+ itemlen -= 4;
memset(&addr, 0, sizeof(addr));
- TCHECK2(pptr[4], (plen + 7) / 8);
- memcpy(&addr, &pptr[4], (plen + 7) / 8);
+ plenbytes = (plen + 7) / 8;
+ TCHECK2(pptr[4], plenbytes);
+ memcpy(&addr, &pptr[4], plenbytes);
if (plen % 8) {
- addr.s6_addr[(plen + 7) / 8 - 1] &=
+ addr.s6_addr[plenbytes - 1] &=
((0xff00 >> (plen % 8)) & 0xff);
}
/* the label may get offsetted by 4 bits so lets shift it right */
EXTRACT_24BITS(pptr+1)>>4,
((pptr[3]&1)==0) ? "(BOGUS: Bottom of Stack NOT set!)" : "(bottom)" );
- return 4 + (plen + 7) / 8;
+ return 4 + plenbytes;
trunc:
return -2;
+
+badtlv:
+ return -3;
}
static int
}
static int
-bgp_attr_print(const struct bgp_attr *attr, const u_char *pptr, int len)
+bgp_attr_print(u_int atype, const u_char *pptr, u_int len)
{
int i;
u_int16_t af;
u_int32_t i;
} bw;
int advance;
- int tlen;
+ u_int tlen;
const u_char *tptr;
char buf[MAXHOSTNAMELEN + 100];
char tokbuf[TOKBUFSIZE];
tptr = pptr;
tlen=len;
- switch (attr->bgpa_type) {
+ switch (atype) {
case BGPTYPE_ORIGIN:
if (len != 1)
printf("invalid len");
* 2 bytes first, and it does not pass, assume that ASs are
* encoded in 4 bytes format and move on.
*/
- as_size = bgp_attr_get_as_size(attr->bgpa_type, pptr, len);
+ as_size = bgp_attr_get_as_size(atype, pptr, len);
while (tptr < pptr + len) {
TCHECK(tptr[0]);
case (AFNUM_INET<<8 | SAFNUM_UNICAST):
case (AFNUM_INET<<8 | SAFNUM_MULTICAST):
case (AFNUM_INET<<8 | SAFNUM_UNIMULTICAST):
- advance = decode_prefix4(tptr, buf, sizeof(buf));
+ advance = decode_prefix4(tptr, len, buf, sizeof(buf));
if (advance == -1)
printf("\n\t (illegal prefix length)");
else if (advance == -2)
goto trunc;
+ else if (advance == -3)
+ break; /* bytes left, but not enough */
else
printf("\n\t %s", buf);
break;
case (AFNUM_INET<<8 | SAFNUM_LABUNICAST):
- advance = decode_labeled_prefix4(tptr, buf, sizeof(buf));
+ advance = decode_labeled_prefix4(tptr, len, buf, sizeof(buf));
if (advance == -1)
printf("\n\t (illegal prefix length)");
else if (advance == -2)
goto trunc;
+ else if (advance == -3)
+ break; /* bytes left, but not enough */
else
printf("\n\t %s", buf);
break;
case (AFNUM_INET6<<8 | SAFNUM_UNICAST):
case (AFNUM_INET6<<8 | SAFNUM_MULTICAST):
case (AFNUM_INET6<<8 | SAFNUM_UNIMULTICAST):
- advance = decode_prefix6(tptr, buf, sizeof(buf));
+ advance = decode_prefix6(tptr, len, buf, sizeof(buf));
if (advance == -1)
printf("\n\t (illegal prefix length)");
else if (advance == -2)
goto trunc;
+ else if (advance == -3)
+ break; /* bytes left, but not enough */
else
printf("\n\t %s", buf);
break;
case (AFNUM_INET6<<8 | SAFNUM_LABUNICAST):
- advance = decode_labeled_prefix6(tptr, buf, sizeof(buf));
+ advance = decode_labeled_prefix6(tptr, len, buf, sizeof(buf));
if (advance == -1)
printf("\n\t (illegal prefix length)");
else if (advance == -2)
goto trunc;
+ else if (advance == -3)
+ break; /* bytes left, but not enough */
else
printf("\n\t %s", buf);
break;
case (AFNUM_INET<<8 | SAFNUM_UNICAST):
case (AFNUM_INET<<8 | SAFNUM_MULTICAST):
case (AFNUM_INET<<8 | SAFNUM_UNIMULTICAST):
- advance = decode_prefix4(tptr, buf, sizeof(buf));
+ advance = decode_prefix4(tptr, len, buf, sizeof(buf));
if (advance == -1)
printf("\n\t (illegal prefix length)");
else if (advance == -2)
goto trunc;
+ else if (advance == -3)
+ break; /* bytes left, but not enough */
else
printf("\n\t %s", buf);
break;
case (AFNUM_INET<<8 | SAFNUM_LABUNICAST):
- advance = decode_labeled_prefix4(tptr, buf, sizeof(buf));
+ advance = decode_labeled_prefix4(tptr, len, buf, sizeof(buf));
if (advance == -1)
printf("\n\t (illegal prefix length)");
else if (advance == -2)
goto trunc;
+ else if (advance == -3)
+ break; /* bytes left, but not enough */
else
printf("\n\t %s", buf);
break;
case (AFNUM_INET6<<8 | SAFNUM_UNICAST):
case (AFNUM_INET6<<8 | SAFNUM_MULTICAST):
case (AFNUM_INET6<<8 | SAFNUM_UNIMULTICAST):
- advance = decode_prefix6(tptr, buf, sizeof(buf));
+ advance = decode_prefix6(tptr, len, buf, sizeof(buf));
if (advance == -1)
printf("\n\t (illegal prefix length)");
else if (advance == -2)
goto trunc;
+ else if (advance == -3)
+ break; /* bytes left, but not enough */
else
printf("\n\t %s", buf);
break;
case (AFNUM_INET6<<8 | SAFNUM_LABUNICAST):
- advance = decode_labeled_prefix6(tptr, buf, sizeof(buf));
+ advance = decode_labeled_prefix6(tptr, len, buf, sizeof(buf));
if (advance == -1)
printf("\n\t (illegal prefix length)");
else if (advance == -2)
goto trunc;
+ else if (advance == -3)
+ break; /* bytes left, but not enough */
else
printf("\n\t %s", buf);
break;
}
case BGPTYPE_ATTR_SET:
TCHECK2(tptr[0], 4);
+ if (len < 4)
+ goto trunc;
printf("\n\t Origin AS: %s",
as_printf(astostr, sizeof(astostr), EXTRACT_32BITS(tptr)));
tptr+=4;
len -=4;
- while (len >= 2 ) {
- int alen;
- struct bgp_attr bgpa;
+ while (len) {
+ u_int aflags, atype, alenlen, alen;
- TCHECK2(tptr[0], sizeof(bgpa));
- memcpy(&bgpa, tptr, sizeof(bgpa));
- alen = bgp_attr_len(&bgpa);
- tptr += bgp_attr_off(&bgpa);
- len -= bgp_attr_off(&bgpa);
+ TCHECK2(tptr[0], 2);
+ if (len < 2)
+ goto trunc;
+ aflags = *tptr;
+ atype = *(tptr + 1);
+ tptr += 2;
+ len -= 2;
+ alenlen = bgp_attr_lenlen(aflags, tptr);
+ TCHECK2(tptr[0], alenlen);
+ if (len < alenlen)
+ goto trunc;
+ alen = bgp_attr_len(aflags, tptr);
+ tptr += alenlen;
+ len -= alenlen;
printf("\n\t %s (%u), length: %u",
tok2strbuf(bgp_attr_values,
- "Unknown Attribute", bgpa.bgpa_type,
- tokbuf, sizeof(tokbuf)),
- bgpa.bgpa_type,
+ "Unknown Attribute", atype,
+ tokbuf, sizeof(tokbuf)),
+ atype,
alen);
- if (bgpa.bgpa_flags) {
+ if (aflags) {
printf(", Flags [%s%s%s%s",
- bgpa.bgpa_flags & 0x80 ? "O" : "",
- bgpa.bgpa_flags & 0x40 ? "T" : "",
- bgpa.bgpa_flags & 0x20 ? "P" : "",
- bgpa.bgpa_flags & 0x10 ? "E" : "");
- if (bgpa.bgpa_flags & 0xf)
- printf("+%x", bgpa.bgpa_flags & 0xf);
+ aflags & 0x80 ? "O" : "",
+ aflags & 0x40 ? "T" : "",
+ aflags & 0x20 ? "P" : "",
+ aflags & 0x10 ? "E" : "");
+ if (aflags & 0xf)
+ printf("+%x", aflags & 0xf);
printf("]: ");
}
/* FIXME check for recursion */
- if (!bgp_attr_print(&bgpa, tptr, alen))
+ if (!bgp_attr_print(atype, tptr, alen))
return 0;
tptr += alen;
len -= alen;
default:
TCHECK2(*pptr,len);
- printf("\n\t no Attribute %u decoder",attr->bgpa_type); /* we have no decoder for the attribute */
+ printf("\n\t no Attribute %u decoder",atype); /* we have no decoder for the attribute */
if (vflag <= 1)
print_unknown_data(pptr,"\n\t ",len);
break;
bgp_update_print(const u_char *dat, int length)
{
struct bgp bgp;
- struct bgp_attr bgpa;
const u_char *p;
+ int withdrawn_routes_len;
int len;
int i;
char tokbuf[TOKBUFSIZE];
TCHECK2(dat[0], BGP_SIZE);
+ if (length < BGP_SIZE)
+ goto trunc;
memcpy(&bgp, dat, BGP_SIZE);
p = dat + BGP_SIZE; /*XXX*/
+ length -= BGP_SIZE;
/* Unfeasible routes */
- len = EXTRACT_16BITS(p);
- if (len) {
+ TCHECK2(p[0], 2);
+ if (length < 2)
+ goto trunc;
+ withdrawn_routes_len = EXTRACT_16BITS(p);
+ p += 2;
+ length -= 2;
+ if (withdrawn_routes_len) {
/*
* Without keeping state from the original NLRI message,
* it's not possible to tell if this a v4 or v6 route,
* so only try to decode it if we're not v6 enabled.
*/
+ TCHECK2(p[0], withdrawn_routes_len);
+ if (length < withdrawn_routes_len)
+ goto trunc;
#ifdef INET6
- printf("\n\t Withdrawn routes: %d bytes", len);
+ printf("\n\t Withdrawn routes: %d bytes", withdrawn_routes_len);
+ p += withdrawn_routes_len;
+ length -= withdrawn_routes_len;
#else
char buf[MAXHOSTNAMELEN + 100];
int wpfx;
- TCHECK2(p[2], len);
- i = 2;
+ if (withdrawn_routes_len < 2)
+ goto trunc;
+ length -= 2;
+ withdrawn_routes_len -= 2;
+
printf("\n\t Withdrawn routes:");
- while(i < 2 + len) {
- wpfx = decode_prefix4(&p[i], buf, sizeof(buf));
+ while(withdrawn_routes_len > 0) {
+ wpfx = decode_prefix4(p, withdrawn_routes_len, buf, sizeof(buf));
if (wpfx == -1) {
printf("\n\t (illegal prefix length)");
break;
} else if (wpfx == -2)
goto trunc;
+ } else if (wpfx == -3)
+ goto trunc; /* bytes left, but not enough */
else {
- i += wpfx;
printf("\n\t %s", buf);
+ p += wpfx;
+ length -= wpfx;
+ withdrawn_routes_len -= wpfx;
}
}
#endif
}
- p += 2 + len;
TCHECK2(p[0], 2);
+ if (length < 2)
+ goto trunc;
len = EXTRACT_16BITS(p);
+ p += 2;
+ length -= 2;
- if (len == 0 && length == BGP_UPDATE_MINSIZE) {
+ if (withdrawn_routes_len == 0 && len == 0 && length == 0) {
+ /* No withdrawn routes, no path attributes, no NLRI */
printf("\n\t End-of-Rib Marker (empty NLRI)");
return;
}
if (len) {
/* do something more useful!*/
- i = 2;
- while (i < 2 + len) {
- int alen, aoff;
-
- TCHECK2(p[i], sizeof(bgpa));
- memcpy(&bgpa, &p[i], sizeof(bgpa));
- alen = bgp_attr_len(&bgpa);
- aoff = bgp_attr_off(&bgpa);
-
- printf("\n\t %s (%u), length: %u",
+ while (len) {
+ int aflags, atype, alenlen, alen;
+
+ TCHECK2(p[0], 2);
+ if (len < 2)
+ goto trunc;
+ if (length < 2)
+ goto trunc;
+ aflags = *p;
+ atype = *(p + 1);
+ p += 2;
+ len -= 2;
+ length -= 2;
+ alenlen = bgp_attr_lenlen(aflags, p);
+ TCHECK2(p[0], alenlen);
+ if (len < alenlen)
+ goto trunc;
+ if (length < alenlen)
+ goto trunc;
+ alen = bgp_attr_len(aflags, p);
+ p += alenlen;
+ len -= alenlen;
+ length -= alenlen;
+
+ printf("\n\t %s (%u), length: %u",
tok2strbuf(bgp_attr_values, "Unknown Attribute",
- bgpa.bgpa_type,
+ atype,
tokbuf, sizeof(tokbuf)),
- bgpa.bgpa_type,
+ atype,
alen);
- if (bgpa.bgpa_flags) {
+ if (aflags) {
printf(", Flags [%s%s%s%s",
- bgpa.bgpa_flags & 0x80 ? "O" : "",
- bgpa.bgpa_flags & 0x40 ? "T" : "",
- bgpa.bgpa_flags & 0x20 ? "P" : "",
- bgpa.bgpa_flags & 0x10 ? "E" : "");
- if (bgpa.bgpa_flags & 0xf)
- printf("+%x", bgpa.bgpa_flags & 0xf);
+ aflags & 0x80 ? "O" : "",
+ aflags & 0x40 ? "T" : "",
+ aflags & 0x20 ? "P" : "",
+ aflags & 0x10 ? "E" : "");
+ if (aflags & 0xf)
+ printf("+%x", aflags & 0xf);
printf("]: ");
}
- if (!bgp_attr_print(&bgpa, &p[i + aoff], alen))
+ if (len < alen)
+ goto trunc;
+ if (length < alen)
goto trunc;
- i += aoff + alen;
+ if (!bgp_attr_print(atype, p, alen))
+ goto trunc;
+ p += alen;
+ len -= alen;
+ length -= alen;
}
}
- p += 2 + len;
- if (dat + length > p) {
+ if (length) {
+ /*
+ * XXX - what if they're using the "Advertisement of
+ * Multiple Paths in BGP" feature:
+ *
+ * https://datatracker.ietf.org/doc/draft-ietf-idr-add-paths/
+ *
+ * http://tools.ietf.org/html/draft-ietf-idr-add-paths-06
+ */
printf("\n\t Updated routes:");
- while (dat + length > p) {
+ while (length) {
char buf[MAXHOSTNAMELEN + 100];
- i = decode_prefix4(p, buf, sizeof(buf));
+ i = decode_prefix4(p, length, buf, sizeof(buf));
if (i == -1) {
printf("\n\t (illegal prefix length)");
break;
} else if (i == -2)
goto trunc;
+ else if (i == -3)
+ goto trunc; /* bytes left, but not enough */
else {
printf("\n\t %s", buf);
p += i;
+ length -= i;
}
}
}
projects / tcpdump / blobdiff