Clean up printing of LLC packets.

Don't print LLC header information for SNAP packets; if we have a SNAP
header, just call snap_print() and return its return value, regardless
of whether it's 1 or 0, don't fall into the code to print raw LLC header
information - and don't print it with -e, either.

If llc_print() returns 0, just call the default packet printer, don't
print the MAC-layer header or the extracted ethertype - llc_print() will
print the source and destination MAC addresses and whatever type
information is in the LLC or SNAP headers.

If we don't know the DSAP/LSAP, and it's an information frame (numbered
or not) and not an XID frame, return 0, so that we give a hex dump of
the raw payload.

In addition, print the length when printing SNAP header information with
-e.

diff --git a/netdissect.h b/netdissect.h
index d7361a4fffcd2b93aaa15fdff6fa113d91a081d9..7cdd53474fb3fa4cf62170aef9b7f302e98c0251 100644 (file)
--- a/netdissect.h
+++ b/netdissect.h
@@ -460,8 +460,9 @@ extern void mpcp_print(netdissect_options *, const u_char *, u_int);
 extern void rpki_rtr_print(netdissect_options *, const u_char *, u_int);
 extern u_int sll_if_print(netdissect_options *, const struct pcap_pkthdr *, const u_char *);
 extern void dccp_print(netdissect_options *, const u_char *, const u_char *, u_int);
-extern int llc_print(netdissect_options *, const u_char *, u_int, u_int, const u_char *, const u_char *, u_short *);
-extern int snap_print(netdissect_options *, const u_char *, u_int, u_int, u_int);
+extern int llc_print(netdissect_options *, const u_char *, u_int, u_int, const u_char *, const u_char *);
+extern int snap_print(netdissect_options *, const u_char *, u_int, u_int,
+       const u_char *, const u_char *, u_int);
 extern void eigrp_print(netdissect_options *, const u_char *, u_int);
 extern void stp_print(netdissect_options *, const u_char *, u_int);
 extern void l2tp_print(netdissect_options *, const u_char *, u_int);

diff --git a/print-802_11.c b/print-802_11.c
index 3c510e8a5a76992821fda9035f6a411f6e1a5831..2c9f2a38be41648eb7834cb4ac5fa6376fb1f51e 100644 (file)
--- a/print-802_11.c
+++ b/print-802_11.c
@@ -2332,7 +2332,6 @@ ieee802_11_print(netdissect_options *ndo,
        uint16_t fc;
        u_int caplen, hdrlen, meshdrlen;
        const uint8_t *src, *dst;
-       u_short extracted_ethertype;
 
        caplen = orig_caplen;
        /* Remove FCS, if present */
@@ -2409,20 +2408,11 @@ ieee802_11_print(netdissect_options *ndo,
                        }
                } else {
                        get_data_src_dst_mac(fc, p - hdrlen, &src, &dst);
-                       if (llc_print(ndo, p, length, caplen, dst, src,
-                           &extracted_ethertype) == 0) {
+                       if (llc_print(ndo, p, length, caplen, dst, src) == 0) {
                                /*
                                 * Some kinds of LLC packet we cannot
                                 * handle intelligently
                                 */
-                               if (!ndo->ndo_eflag) {
-                                       ieee_802_11_hdr_print(ndo, fc, p - hdrlen,
-                                           hdrlen, meshdrlen);
-                               }
-                               if (extracted_ethertype)
-                                       ND_PRINT((ndo, "(LLC %s) ",
-                                           etherproto_string(
-                                               htons(extracted_ethertype))));
                                if (!ndo->ndo_suppress_default_print)
                                        ND_DEFAULTPRINT(p, caplen);
                        }

diff --git a/print-atm.c b/print-atm.c
index b5d3385f4671e69622c8aeadeec524e0d2240498..82a012ba03139ac35224a06169b9da88bc1bdc5a 100644 (file)
--- a/print-atm.c
+++ b/print-atm.c
@@ -218,15 +218,8 @@ static void
 atm_llc_print(netdissect_options *ndo,
               const u_char *p, int length, int caplen)
 {
-       u_short extracted_ethertype;
-
-       if (!llc_print(ndo, p, length, caplen, NULL, NULL,
-           &extracted_ethertype)) {
+       if (!llc_print(ndo, p, length, caplen, NULL, NULL)) {
                /* ether_type not known, print raw packet */
-               if (extracted_ethertype) {
-                       ND_PRINT((ndo, "(LLC %s) ",
-               etherproto_string(htons(extracted_ethertype))));
-               }
                if (!ndo->ndo_suppress_default_print)
                        ND_DEFAULTPRINT(p, caplen);
        }

diff --git a/print-cip.c b/print-cip.c
index fadb83be69f82724192c43ba50fcd983d4141e84..23f6178808d5d38e6d57bba58bd4984371cd4777 100644 (file)
--- a/print-cip.c
+++ b/print-cip.c
@@ -61,7 +61,6 @@ cip_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char
 {
        u_int caplen = h->caplen;
        u_int length = h->len;
-       u_short extracted_ethertype;
 
        if (memcmp(rfcllc, p, sizeof(rfcllc))==0 && caplen < RFC1483LLC_LEN) {
                ND_PRINT((ndo, "[|cip]"));
@@ -75,15 +74,7 @@ cip_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char
                /*
                 * LLC header is present.  Try to print it & higher layers.
                 */
-               if (llc_print(ndo, p, length, caplen, NULL, NULL,
-                   &extracted_ethertype) == 0) {
-                       /* ether_type not known, print raw packet */
-                       if (!ndo->ndo_eflag)
-                               cip_print(ndo, length);
-                       if (extracted_ethertype) {
-                               ND_PRINT((ndo, "(LLC %s) ",
-                              etherproto_string(htons(extracted_ethertype))));
-                       }
+               if (llc_print(ndo, p, length, caplen, NULL, NULL) == 0) {
                        if (!ndo->ndo_suppress_default_print)
                                ND_DEFAULTPRINT(p, caplen);
                }

diff --git a/print-ether.c b/print-ether.c
index e491515cf527ecde346126904f7da59647962464..26c5c97c9c3005dddb83e6299e22c6e4329e603f 100644 (file)
--- a/print-ether.c
+++ b/print-ether.c
@@ -130,7 +130,6 @@ ether_print(netdissect_options *ndo,
        struct ether_header *ep;
        u_int orig_length;
        u_short ether_type;
-       u_short extracted_ether_type;
 
        if (caplen < ETHER_HDRLEN || length < ETHER_HDRLEN) {
                ND_PRINT((ndo, "[|ether]"));
@@ -157,15 +156,8 @@ recurse:
         */
        if (ether_type <= ETHERMTU) {
                /* Try to print the LLC-layer header & higher layers */
-               if (llc_print(ndo, p, length, caplen, ESRC(ep), EDST(ep),
-                   &extracted_ether_type) == 0) {
+               if (llc_print(ndo, p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
                        /* ether_type not known, print raw packet */
-                       if (!ndo->ndo_eflag) {
-                               if (print_encap_header != NULL)
-                                       (*print_encap_header)(ndo, encap_header_arg);
-                               ether_hdr_print(ndo, (u_char *)ep, orig_length);
-                       }
-
                        if (!ndo->ndo_suppress_default_print)
                                ND_DEFAULTPRINT(p, caplen);
                }
@@ -205,15 +197,8 @@ recurse:
                 * there's an LLC header and payload.
                 */
                /* Try to print the LLC-layer header & higher layers */
-               if (llc_print(ndo, p, length, caplen, ESRC(ep), EDST(ep),
-                   &extracted_ether_type) == 0) {
+               if (llc_print(ndo, p, length, caplen, ESRC(ep), EDST(ep)) == 0) {
                        /* ether_type not known, print raw packet */
-                       if (!ndo->ndo_eflag) {
-                               if (print_encap_header != NULL)
-                                       (*print_encap_header)(ndo, encap_header_arg);
-                               ether_hdr_print(ndo, (u_char *)ep, orig_length);
-                       }
-
                        if (!ndo->ndo_suppress_default_print)
                                ND_DEFAULTPRINT(p, caplen);
                }

diff --git a/print-fddi.c b/print-fddi.c
index 04ab0f67072b5e052aa207330c15f879ac4ba9db..9e6ec0b1024226213ca8e729ff66a9511093be73 100644 (file)
--- a/print-fddi.c
+++ b/print-fddi.c
@@ -282,7 +282,6 @@ fddi_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen)
 {
        const struct fddi_header *fddip = (const struct fddi_header *)p;
        struct ether_header ehdr;
-       u_short extracted_ethertype;
 
        if (caplen < FDDI_HDRLEN) {
                ND_PRINT((ndo, "[|fddi]"));
@@ -305,19 +304,11 @@ fddi_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen)
        /* Frame Control field determines interpretation of packet */
        if ((fddip->fddi_fc & FDDIFC_CLFF) == FDDIFC_LLC_ASYNC) {
                /* Try to print the LLC-layer header & higher layers */
-               if (llc_print(ndo, p, length, caplen, ESRC(&ehdr), EDST(&ehdr),
-                   &extracted_ethertype) == 0) {
+               if (llc_print(ndo, p, length, caplen, ESRC(&ehdr), EDST(&ehdr)) == 0) {
                        /*
                         * Some kinds of LLC packet we cannot
                         * handle intelligently
                         */
-                       if (!ndo->ndo_eflag)
-                               fddi_hdr_print(ndo, fddip, length + FDDI_HDRLEN,
-                                   ESRC(&ehdr), EDST(&ehdr));
-                       if (extracted_ethertype) {
-                               ND_PRINT((ndo, "(LLC %s) ",
-                       etherproto_string(htons(extracted_ethertype))));
-                       }
                        if (!ndo->ndo_suppress_default_print)
                                ND_DEFAULTPRINT(p, caplen);
                }

diff --git a/print-fr.c b/print-fr.c
index d7dfe6c7cc37ba384e96ea67a256bbec9df3ea86..17321b1459e3cb6d9d302786129ead6b7449a77c 100644 (file)
--- a/print-fr.c
+++ b/print-fr.c
@@ -330,7 +330,7 @@ fr_print(netdissect_options *ndo,
                break;
 
        case NLPID_SNAP:
-               if (snap_print(ndo, p, length, length, 0) == 0) {
+               if (snap_print(ndo, p, length, length, NULL, NULL, 0) == 0) {
                        /* ether_type not known, print raw packet */
                         if (!ndo->ndo_eflag)
                             fr_hdr_print(ndo, length + hdr_len, hdr_len,

diff --git a/print-ipfc.c b/print-ipfc.c
index 6c92f901f1d81c68b410e4305db5f0310eaf1083..b2869eb81318f6ceb73dc81ee9893c351f33981f 100644 (file)
--- a/print-ipfc.c
+++ b/print-ipfc.c
@@ -81,7 +81,6 @@ ipfc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen)
 {
        const struct ipfc_header *ipfcp = (const struct ipfc_header *)p;
        struct ether_header ehdr;
-       u_short extracted_ethertype;
 
        if (caplen < IPFC_HDRLEN) {
                ND_PRINT((ndo, "[|ipfc]"));
@@ -101,19 +100,11 @@ ipfc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen)
        caplen -= IPFC_HDRLEN;
 
        /* Try to print the LLC-layer header & higher layers */
-       if (llc_print(ndo, p, length, caplen, ESRC(&ehdr), EDST(&ehdr),
-           &extracted_ethertype) == 0) {
+       if (llc_print(ndo, p, length, caplen, ESRC(&ehdr), EDST(&ehdr)) == 0) {
                /*
                 * Some kinds of LLC packet we cannot
                 * handle intelligently
                 */
-               if (!ndo->ndo_eflag)
-                       ipfc_hdr_print(ndo, ipfcp, length + IPFC_HDRLEN,
-                           ESRC(&ehdr), EDST(&ehdr));
-               if (extracted_ethertype) {
-                       ND_PRINT((ndo, "(LLC %s) ",
-               etherproto_string(htons(extracted_ethertype))));
-               }
                if (!ndo->ndo_suppress_default_print)
                        ND_DEFAULTPRINT(p, caplen);
        }

diff --git a/print-juniper.c b/print-juniper.c
index 750f76abe8268445a6c29d32380ee36792eb9dc1..d402c00d0fac6d2ab48184b2002c702617580a36 100644 (file)
--- a/print-juniper.c
+++ b/print-juniper.c
@@ -937,8 +937,7 @@ juniper_atm1_print(netdissect_options *ndo,
         if (EXTRACT_24BITS(p) == 0xfefe03 || /* NLPID encaps ? */
             EXTRACT_24BITS(p) == 0xaaaa03) { /* SNAP encaps ? */
 
-            if (llc_print(ndo, p, l2info.length, l2info.caplen, NULL, NULL,
-                          &extracted_ethertype) != 0)
+            if (llc_print(ndo, p, l2info.length, l2info.caplen, NULL, NULL) != 0)
                 return l2info.header_len;
         }
 
@@ -986,8 +985,7 @@ juniper_atm2_print(netdissect_options *ndo,
         if (EXTRACT_24BITS(p) == 0xfefe03 || /* NLPID encaps ? */
             EXTRACT_24BITS(p) == 0xaaaa03) { /* SNAP encaps ? */
 
-            if (llc_print(ndo, p, l2info.length, l2info.caplen, NULL, NULL,
-                          &extracted_ethertype) != 0)
+            if (llc_print(ndo, p, l2info.length, l2info.caplen, NULL, NULL) != 0)
                 return l2info.header_len;
         }
 

diff --git a/print-llc.c b/print-llc.c
index fc83802893c5faf8a0aa5f362d0bf5ac153ea632..5681b49569b9e66ad21dc24f153bc9d4ef485052 100644 (file)
--- a/print-llc.c
+++ b/print-llc.c
@@ -137,18 +137,17 @@ static const struct oui_tok oui_to_tok[] = {
 };
 
 /*
- * Returns non-zero IFF it succeeds in printing the header
+ * Returns zero if we have a payload but haven't printed it (for example,
+ * because it has unknown SAPs or has a SNAP header with an unknown OUI/
+ * PID combination).
  */
 int
 llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
-         const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
+         const u_char *esrc, const u_char *edst)
 {
        uint8_t dsap_field, dsap, ssap_field, ssap;
        uint16_t control;
        int is_u;
-       register int ret;
-
-       *extracted_ethertype = 0;
 
        if (caplen < 3 || length < 3) {
                ND_PRINT((ndo, "[|llc]"));
@@ -215,6 +214,23 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
        dsap = dsap_field & ~LLC_IG;
        ssap = ssap_field & ~LLC_GSAP;
 
+       /*
+        * Check for SNAP UI packets; if we have one, there's no point
+        * in printing the LLC header information, as we already know it -
+        * the relevant protocol-selection information is the SNAP OUI
+        * and PID, so it's sufficient to print that for frames we
+        * don't know how to print and for the "-e" flag.
+        */
+       if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
+           && control == LLC_UI) {
+               /*
+                * XXX - what *is* the right bridge pad value here?
+                * Does anybody ever bridge one form of LAN traffic
+                * over a networking type that uses 802.2 LLC?
+                */
+               return (snap_print(ndo, p+3, length-3, caplen-3, esrc, edst, 2));
+       }
+
        if (ndo->ndo_eflag) {
                 ND_PRINT((ndo, "LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
                        tok2str(llc_values, "Unknown", dsap),
@@ -298,18 +314,6 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                return (1);
        }
 
-       if (ssap == LLCSAP_SNAP && dsap == LLCSAP_SNAP
-           && control == LLC_UI) {
-               /*
-                * XXX - what *is* the right bridge pad value here?
-                * Does anybody ever bridge one form of LAN traffic
-                * over a networking type that uses 802.2 LLC?
-                */
-               ret = snap_print(ndo, p+3, length-3, caplen-3, 2);
-               if (ret)
-                       return (ret);
-       }
-
        if (!ndo->ndo_eflag) {
                if (ssap == dsap) {
                        if (esrc == NULL || edst == NULL)
@@ -344,6 +348,7 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                if ((control & ~LLC_U_POLL) == LLC_XID) {
                        if (*p == LLC_XID_FI) {
                                ND_PRINT((ndo, ": %02x %02x", p[1], p[2]));
+                               return (1);
                        }
                }
        } else {
@@ -353,6 +358,7 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                                LLC_IS_NR(control),
                                tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
                                 length));
+                       return (1);     /* no payload to print */
                } else {
                        ND_PRINT((ndo, "Information, send seq %u, rcv seq %u, Flags [%s], length %u",
                                LLC_I_NS(control),
@@ -361,11 +367,38 @@ llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                                 length));
                }
        }
-       return(1);
+       return (0);
+}
+
+static void
+snap_hdr_print(netdissect_options *ndo, const uint8_t *esrc, const uint8_t *edst,
+       uint32_t orgcode, u_short et, u_int length)
+{
+       const struct tok *tok = null_values;
+       const struct oui_tok *otp;
+
+       if (esrc != NULL && edst != NULL) {
+               ND_PRINT((ndo, "%s > %s ",
+                               etheraddr_string(ndo, esrc),
+                               etheraddr_string(ndo, edst)));
+       }
+       for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
+               if (otp->oui == orgcode) {
+                       tok = otp->tok;
+                       break;
+               }
+       }
+       ND_PRINT((ndo, "SNAP oui %s (0x%06x), %s %s (0x%04x), length %u: ",
+            tok2str(oui_values, "Unknown", orgcode),
+            orgcode,
+            (orgcode == 0x000000 ? "ethertype" : "pid"),
+            tok2str(tok, "Unknown", et),
+            et, length));
 }
 
 int
-snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen, u_int bridge_pad)
+snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
+       const u_char *esrc, const u_char *edst, u_int bridge_pad)
 {
        uint32_t orgcode;
        register u_short et;
@@ -378,21 +411,11 @@ snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
        et = EXTRACT_16BITS(p + 3);
 
        if (ndo->ndo_eflag) {
-               const struct tok *tok = null_values;
-               const struct oui_tok *otp;
-
-               for (otp = &oui_to_tok[0]; otp->tok != NULL; otp++) {
-                       if (otp->oui == orgcode) {
-                               tok = otp->tok;
-                               break;
-                       }
-               }
-               ND_PRINT((ndo, "oui %s (0x%06x), %s %s (0x%04x): ",
-                    tok2str(oui_values, "Unknown", orgcode),
-                    orgcode,
-                    (orgcode == 0x000000 ? "ethertype" : "pid"),
-                    tok2str(tok, "Unknown", et),
-                    et));
+               /*
+                * Somebody's already printed the MAC addresses, if there
+                * are any, so just print the SNAP header.
+                */
+               snap_hdr_print(ndo, NULL, NULL, orgcode, et, length - 5);
        }
        p += 5;
        length -= 5;
@@ -521,6 +544,8 @@ snap_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
                        return (1);
                }
        }
+       if (!ndo->ndo_eflag)
+               snap_hdr_print(ndo, esrc, edst, orgcode, et, length);
        return (0);
 
 trunc:

diff --git a/print-sll.c b/print-sll.c
index 76b4e95f2ffa50a25b3f44cbb96a4ef0bf3247f8..e15afa9e44663b665eeaf6cae0df56d1236b4e59 100644 (file)
--- a/print-sll.c
+++ b/print-sll.c
@@ -197,7 +197,6 @@ sll_if_print(netdissect_options *ndo, const struct pcap_pkthdr *h, const u_char
        u_int length = h->len;
        register const struct sll_header *sllp;
        u_short ether_type;
-       u_short extracted_ethertype;
 
        if (caplen < SLL_HDR_LEN) {
                /*
@@ -246,23 +245,15 @@ recurse:
                         * 802.2.
                         * Try to print the LLC-layer header & higher layers.
                         */
-                       if (llc_print(ndo, p, length, caplen, NULL, NULL,
-                           &extracted_ethertype) == 0)
+                       if (llc_print(ndo, p, length, caplen, NULL, NULL) == 0)
                                goto unknown;   /* unknown LLC type */
                        break;
 
                default:
-                       extracted_ethertype = 0;
                        /*FALLTHROUGH*/
 
                unknown:
                        /* ether_type not known, print raw packet */
-                       if (!ndo->ndo_eflag)
-                               sll_print(ndo, sllp, length + SLL_HDR_LEN);
-                       if (extracted_ethertype) {
-                               ND_PRINT((ndo, "(LLC %s) ",
-                              etherproto_string(htons(extracted_ethertype))));
-                       }
                        if (!ndo->ndo_suppress_default_print)
                                ND_DEFAULTPRINT(p, caplen);
                        break;

diff --git a/print-token.c b/print-token.c
index 33647a14c069cc4c149c4f45bdb714ea285cfaec..9a0e974279a027d4b620392e792c48026cea9e88 100644 (file)
--- a/print-token.c
+++ b/print-token.c
@@ -148,7 +148,6 @@ u_int
 token_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen)
 {
        const struct token_header *trp;
-       u_short extracted_ethertype;
        struct ether_header ehdr;
        u_int route_len = 0, hdr_len = TOKEN_HDRLEN;
        int seg;
@@ -210,17 +209,8 @@ token_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen
        /* Frame Control field determines interpretation of packet */
        if (FRAME_TYPE(trp) == TOKEN_FC_LLC) {
                /* Try to print the LLC-layer header & higher layers */
-               if (llc_print(ndo, p, length, caplen, ESRC(&ehdr), EDST(&ehdr),
-                   &extracted_ethertype) == 0) {
+               if (llc_print(ndo, p, length, caplen, ESRC(&ehdr), EDST(&ehdr)) == 0) {
                        /* ether_type not known, print raw packet */
-                       if (!ndo->ndo_eflag)
-                               token_hdr_print(ndo, trp,
-                                   length + TOKEN_HDRLEN + route_len,
-                                   ESRC(&ehdr), EDST(&ehdr));
-                       if (extracted_ethertype) {
-                               ND_PRINT((ndo, "(LLC %s) ",
-                       etherproto_string(htons(extracted_ethertype))));
-                       }
                        if (!ndo->ndo_suppress_default_print)
                                ND_DEFAULTPRINT(p, caplen);
                }