/*
* If we printed information about the payload, returns the length of the LLC
* header, plus the length of any SNAP header following it.
*
* Otherwise (for example, if the packet has unknown SAPs or has a SNAP
* header with an unknown OUI/PID combination), returns the *negative*
* of that value.
*/
int
llc_print(netdissect_options *ndo, const u_char *p, u_int length, u_int caplen,
const struct lladdr_info *src, const struct lladdr_info *dst)
{
uint8_t dsap_field, dsap, ssap_field, ssap;
uint16_t control;
int hdrlen;
int is_u;
if (caplen < 3) {
ND_PRINT("[|llc]");
ND_DEFAULTPRINT((const u_char *)p, caplen);
return (caplen);
}
if (length < 3) {
ND_PRINT("[|llc]");
ND_DEFAULTPRINT((const u_char *)p, caplen);
return (length);
}
dsap_field = EXTRACT_U_1(p);
ssap_field = EXTRACT_U_1(p + 1);
/*
* OK, what type of LLC frame is this? The length
* of the control field depends on that - I frames
* have a two-byte control field, and U frames have
* a one-byte control field.
*/
control = EXTRACT_U_1(p + 2);
if ((control & LLC_U_FMT) == LLC_U_FMT) {
/*
* U frame.
*/
is_u = 1;
hdrlen = 3; /* DSAP, SSAP, 1-byte control field */
} else {
/*
* The control field in I and S frames is
* 2 bytes...
*/
if (caplen < 4) {
ND_PRINT("[|llc]");
ND_DEFAULTPRINT((const u_char *)p, caplen);
return (caplen);
}
if (length < 4) {
ND_PRINT("[|llc]");
ND_DEFAULTPRINT((const u_char *)p, caplen);
return (length);
}
/*
* ...and is little-endian.
*/
control = EXTRACT_LE_U_2(p + 2);
is_u = 0;
hdrlen = 4; /* DSAP, SSAP, 2-byte control field */
}
if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) {
/*
* This is an Ethernet_802.3 IPX frame; it has an
* 802.3 header (i.e., an Ethernet header where the
* type/length field is <= MAX_ETHERNET_LENGTH_VAL,
* i.e. it's a length field, not a type field), but
* has no 802.2 header - the IPX packet starts right
* after the Ethernet header, with a signature of two
* bytes of 0xFF (which is LLCSAP_GLOBAL).
*
* (It might also have been an Ethernet_802.3 IPX at
* one time, but got bridged onto another network,
* such as an 802.11 network; this has appeared in at
* least one capture file.)
*/
if (ndo->ndo_eflag)
ND_PRINT("IPX 802.3: ");
ipx_print(ndo, p, length);
return (0); /* no LLC header */
}
dsap = dsap_field & ~LLC_IG;
ssap = ssap_field & ~LLC_GSAP;
if (ndo->ndo_eflag) {
ND_PRINT("LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
tok2str(llc_values, "Unknown", dsap),
dsap,
tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
tok2str(llc_values, "Unknown", ssap),
ssap,
tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP));
if (is_u) {
ND_PRINT(", ctrl 0x%02x: ", control);
} else {
ND_PRINT(", ctrl 0x%04x: ", control);
}
}
/*
* Skip LLC header.
*/
p += hdrlen;
length -= hdrlen;
caplen -= hdrlen;
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?
*/
if (!snap_print(ndo, p, length, caplen, src, dst, 2)) {
/*
* Unknown packet type; tell our caller, by
* returning a negative value, so they
* can print the raw packet.
*/
return (-(hdrlen + 5)); /* include LLC and SNAP header */
} else
return (hdrlen + 5); /* include LLC and SNAP header */
}
if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
control == LLC_UI) {
stp_print(ndo, p, length);
return (hdrlen);
}
if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
control == LLC_UI) {
/*
* This is an RFC 948-style IP packet, with
* an 802.3 header and an 802.2 LLC header
* with the source and destination SAPs being
* the IP SAP.
*/
ip_print(ndo, p, length);
return (hdrlen);
}
if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
control == LLC_UI) {
/*
* This is an Ethernet_802.2 IPX frame, with an 802.3
* header and an 802.2 LLC header with the source and
* destination SAPs being the IPX SAP.
*/
if (ndo->ndo_eflag)
ND_PRINT("IPX 802.2: ");
ipx_print(ndo, p, length);
return (hdrlen);
}
#ifdef ENABLE_SMB
if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
&& (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
/*
* we don't actually have a full netbeui parser yet, but the
* smb parser can handle many smb-in-netbeui packets, which
* is very useful, so we call that
*
* We don't call it for S frames, however, just I frames
* (which are frames that don't have the low-order bit,
* LLC_S_FMT, set in the first byte of the control field)
* and UI frames (whose control field is just 3, LLC_U_FMT).
*/
netbeui_print(ndo, control, p, length);
return (hdrlen);
}
#endif
if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
&& control == LLC_UI) {
isoclns_print(ndo, p, length);
return (hdrlen);
}
if (!ndo->ndo_eflag) {
if (ssap == dsap) {
if (src == NULL || dst == NULL)
ND_PRINT("%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
else
ND_PRINT("%s > %s %s ",
(src->addr_string)(ndo, src->addr),
(dst->addr_string)(ndo, dst->addr),
tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
} else {
if (src == NULL || dst == NULL)
ND_PRINT("%s > %s ",
tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
else
ND_PRINT("%s %s > %s %s ",
(src->addr_string)(ndo, src->addr),
tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
(dst->addr_string)(ndo, dst->addr),
tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
}
}
if (is_u) {
ND_PRINT("Unnumbered, %s, Flags [%s], length %u",
tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)),
tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)),
length + hdrlen);
if ((control & ~LLC_U_POLL) == LLC_XID) {
if (length == 0) {
/*
* XID with no payload.
* This could, for example, be an SNA
* "short form" XID.
*/
return (hdrlen);
}
if (caplen < 1) {
ND_PRINT("[|llc]");
if (caplen > 0)
ND_DEFAULTPRINT((const u_char *)p, caplen);
return (hdrlen);
}
if (EXTRACT_U_1(p) == LLC_XID_FI) {
if (caplen < 3 || length < 3) {
ND_PRINT("[|llc]");
if (caplen > 0)
ND_DEFAULTPRINT((const u_char *)p, caplen);
} else
ND_PRINT(": %02x %02x",
EXTRACT_U_1(p + 1),
EXTRACT_U_1(p + 2));
return (hdrlen);
}
}
} else {
if ((control & LLC_S_FMT) == LLC_S_FMT) {
ND_PRINT("Supervisory, %s, rcv seq %u, Flags [%s], length %u",
tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)),
LLC_IS_NR(control),
tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
length + hdrlen);
return (hdrlen); /* no payload to print */
} else {
ND_PRINT("Information, send seq %u, rcv seq %u, Flags [%s], length %u",
LLC_I_NS(control),
LLC_IS_NR(control),
tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
length + hdrlen);
}
}
return (-hdrlen);
}
int
llc_print(const u_char *p, u_int length, u_int caplen,
const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
{
u_int8_t dsap_field, dsap, ssap_field, ssap;
u_int16_t control;
int is_u;
register int ret;
*extracted_ethertype = 0;
if (caplen < 3) {
(void)printf("[|llc]");
default_print((u_char *)p, caplen);
return(0);
}
dsap_field = *p;
ssap_field = *(p + 1);
/*
* OK, what type of LLC frame is this? The length
* of the control field depends on that - I frames
* have a two-byte control field, and U frames have
* a one-byte control field.
*/
control = *(p + 2);
if ((control & LLC_U_FMT) == LLC_U_FMT) {
/*
* U frame.
*/
is_u = 1;
} else {
/*
* The control field in I and S frames is
* 2 bytes...
*/
if (caplen < 4) {
(void)printf("[|llc]");
default_print((u_char *)p, caplen);
return(0);
}
/*
* ...and is little-endian.
*/
control = EXTRACT_LE_16BITS(p + 2);
is_u = 0;
}
if (ssap_field == LLCSAP_GLOBAL && dsap_field == LLCSAP_GLOBAL) {
/*
* This is an Ethernet_802.3 IPX frame; it has an
* 802.3 header (i.e., an Ethernet header where the
* type/length field is <= ETHERMTU, i.e. it's a length
* field, not a type field), but has no 802.2 header -
* the IPX packet starts right after the Ethernet header,
* with a signature of two bytes of 0xFF (which is
* LLCSAP_GLOBAL).
*
* (It might also have been an Ethernet_802.3 IPX at
* one time, but got bridged onto another network,
* such as an 802.11 network; this has appeared in at
* least one capture file.)
*/
if (eflag)
printf("IPX 802.3: ");
ipx_print(p, length);
return (1);
}
dsap = dsap_field & ~LLC_IG;
ssap = ssap_field & ~LLC_GSAP;
if (eflag) {
printf("LLC, dsap %s (0x%02x) %s, ssap %s (0x%02x) %s",
tok2str(llc_values, "Unknown", dsap),
dsap,
tok2str(llc_ig_flag_values, "Unknown", dsap_field & LLC_IG),
tok2str(llc_values, "Unknown", ssap),
ssap,
tok2str(llc_flag_values, "Unknown", ssap_field & LLC_GSAP));
if (is_u) {
printf(", ctrl 0x%02x: ", control);
} else {
printf(", ctrl 0x%04x: ", control);
}
}
if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
control == LLC_UI) {
stp_print(p+3, length-3);
return (1);
}
if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
control == LLC_UI) {
ip_print(gndo, p+4, length-4);
return (1);
}
if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
control == LLC_UI) {
/*
* This is an Ethernet_802.2 IPX frame, with an 802.3
* header and an 802.2 LLC header with the source and
* destination SAPs being the IPX SAP.
*
* Skip DSAP, LSAP, and control field.
*/
if (eflag)
printf("IPX 802.2: ");
ipx_print(p+3, length-3);
return (1);
}
#ifdef TCPDUMP_DO_SMB
if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
&& (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
/*
* we don't actually have a full netbeui parser yet, but the
* smb parser can handle many smb-in-netbeui packets, which
* is very useful, so we call that
*
* We don't call it for S frames, however, just I frames
* (which are frames that don't have the low-order bit,
* LLC_S_FMT, set in the first byte of the control field)
* and UI frames (whose control field is just 3, LLC_U_FMT).
*/
/*
* Skip the LLC header.
*/
if (is_u) {
p += 3;
length -= 3;
caplen -= 3;
} else {
p += 4;
length -= 4;
caplen -= 4;
}
netbeui_print(control, p, length);
return (1);
}
#endif
if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
&& control == LLC_UI) {
isoclns_print(p + 3, length - 3, caplen - 3);
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(p+3, length-3, caplen-3, extracted_ethertype,
2);
if (ret)
return (ret);
}
if (!eflag) {
if (ssap == dsap) {
if (esrc == NULL || edst == NULL)
(void)printf("%s ", tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
else
(void)printf("%s > %s %s ",
etheraddr_string(esrc),
etheraddr_string(edst),
tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
} else {
if (esrc == NULL || edst == NULL)
(void)printf("%s > %s ",
tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
else
(void)printf("%s %s > %s %s ",
etheraddr_string(esrc),
tok2str(llc_values, "Unknown SSAP 0x%02x", ssap),
etheraddr_string(edst),
tok2str(llc_values, "Unknown DSAP 0x%02x", dsap));
}
}
if (is_u) {
printf("Unnumbered, %s, Flags [%s], length %u",
tok2str(llc_cmd_values, "%02x", LLC_U_CMD(control)),
tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_U_POLL)),
length);
p += 3;
length -= 3;
caplen -= 3;
if ((control & ~LLC_U_POLL) == LLC_XID) {
if (*p == LLC_XID_FI) {
printf(": %02x %02x", p[1], p[2]);
p += 3;
length -= 3;
caplen -= 3;
}
}
} else {
if ((control & LLC_S_FMT) == LLC_S_FMT) {
(void)printf("Supervisory, %s, rcv seq %u, Flags [%s], length %u",
tok2str(llc_supervisory_values,"?",LLC_S_CMD(control)),
LLC_IS_NR(control),
tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
length);
} else {
(void)printf("Information, send seq %u, rcv seq %u, Flags [%s], length %u",
LLC_I_NS(control),
LLC_IS_NR(control),
tok2str(llc_flag_values,"?",(ssap_field & LLC_GSAP) | (control & LLC_IS_POLL)),
length);
}
p += 4;
length -= 4;
caplen -= 4;
}
return(1);
}
/*
* Returns non-zero IFF it succeeds in printing the header
*/
int
llc_print(const u_char *p, u_int length, u_int caplen,
const u_char *esrc, const u_char *edst, u_short *extracted_ethertype)
{
u_int8_t dsap, ssap;
u_int16_t control;
int is_u;
register int ret;
if (caplen < 3) {
(void)printf("[|llc]");
default_print((u_char *)p, caplen);
return(0);
}
dsap = *p;
ssap = *(p + 1);
/*
* OK, what type of LLC frame is this? The length
* of the control field depends on that - I frames
* have a two-byte control field, and U frames have
* a one-byte control field.
*/
control = *(p + 2);
if ((control & LLC_U_FMT) == LLC_U_FMT) {
/*
* U frame.
*/
is_u = 1;
} else {
/*
* The control field in I and S frames is
* 2 bytes...
*/
if (caplen < 4) {
(void)printf("[|llc]");
default_print((u_char *)p, caplen);
return(0);
}
/*
* ...and is little-endian.
*/
control = EXTRACT_LE_16BITS(p + 2);
is_u = 0;
}
#if !defined(EMBED) || defined(CONFIG_IPX) || defined(CONFIG_IPX_MODULE)
if (ssap == LLCSAP_GLOBAL && dsap == LLCSAP_GLOBAL) {
/*
* This is an Ethernet_802.3 IPX frame; it has an
* 802.3 header (i.e., an Ethernet header where the
* type/length field is <= ETHERMTU, i.e. it's a length
* field, not a type field), but has no 802.2 header -
* the IPX packet starts right after the Ethernet header,
* with a signature of two bytes of 0xFF (which is
* LLCSAP_GLOBAL).
*
* (It might also have been an Ethernet_802.3 IPX at
* one time, but got bridged onto another network,
* such as an 802.11 network; this has appeared in at
* least one capture file.)
*/
if (eflag)
printf("IPX-802.3: ");
ipx_print(p, length);
return (1);
}
#endif
if (eflag) {
if (is_u) {
printf("LLC, dsap %s (0x%02x), ssap %s (0x%02x), cmd 0x%02x: ",
tok2str(llc_values, "Unknown", dsap),
dsap,
tok2str(llc_values, "Unknown", ssap),
ssap,
control);
} else {
printf("LLC, dsap %s (0x%02x), ssap %s (0x%02x), cmd 0x%04x: ",
tok2str(llc_values, "Unknown", dsap),
dsap,
tok2str(llc_values, "Unknown", ssap),
ssap,
control);
}
}
#if !defined(EMBED) || defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)
if (ssap == LLCSAP_8021D && dsap == LLCSAP_8021D &&
control == LLC_UI) {
stp_print(p+3, length-3);
return (1);
}
#endif
if (ssap == LLCSAP_IP && dsap == LLCSAP_IP &&
control == LLC_UI) {
ip_print(gndo, p+4, length-4);
return (1);
}
#if !defined(EMBED) || defined(CONFIG_IPX) || defined(CONFIG_IPX_MODULE)
if (ssap == LLCSAP_IPX && dsap == LLCSAP_IPX &&
control == LLC_UI) {
/*
* This is an Ethernet_802.2 IPX frame, with an 802.3
* header and an 802.2 LLC header with the source and
* destination SAPs being the IPX SAP.
*
* Skip DSAP, LSAP, and control field.
*/
printf("(NOV-802.2) ");
ipx_print(p+3, length-3);
return (1);
}
#endif
#ifdef TCPDUMP_DO_SMB
if (ssap == LLCSAP_NETBEUI && dsap == LLCSAP_NETBEUI
&& (!(control & LLC_S_FMT) || control == LLC_U_FMT)) {
/*
* we don't actually have a full netbeui parser yet, but the
* smb parser can handle many smb-in-netbeui packets, which
* is very useful, so we call that
*
* We don't call it for S frames, however, just I frames
* (which are frames that don't have the low-order bit,
* LLC_S_FMT, set in the first byte of the control field)
* and UI frames (whose control field is just 3, LLC_U_FMT).
*/
/*
* Skip the LLC header.
*/
if (is_u) {
p += 3;
length -= 3;
caplen -= 3;
} else {
p += 4;
length -= 4;
caplen -= 4;
}
netbeui_print(control, p, length);
return (1);
}
#endif
#if !defined(EMBED)
if (ssap == LLCSAP_ISONS && dsap == LLCSAP_ISONS
&& control == LLC_UI) {
isoclns_print(p + 3, length - 3, caplen - 3);
return (1);
}
#endif
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(p+3, length-3, caplen-3, extracted_ethertype,
2);
if (ret)
return (ret);
}
if (!eflag) {
if ((ssap & ~LLC_GSAP) == dsap) {
if (esrc == NULL || edst == NULL)
(void)printf("%s ", llcsap_string(dsap));
else
(void)printf("%s > %s %s ",
etheraddr_string(esrc),
etheraddr_string(edst),
llcsap_string(dsap));
} else {
if (esrc == NULL || edst == NULL)
(void)printf("%s > %s ",
llcsap_string(ssap & ~LLC_GSAP),
llcsap_string(dsap));
else
(void)printf("%s %s > %s %s ",
etheraddr_string(esrc),
llcsap_string(ssap & ~LLC_GSAP),
etheraddr_string(edst),
llcsap_string(dsap));
}
}
if (is_u) {
const char *m;
char f;
m = tok2str(cmd2str, "%02x", LLC_U_CMD(control));
switch ((ssap & LLC_GSAP) | (control & LLC_U_POLL)) {
case 0: f = 'C'; break;
case LLC_GSAP: f = 'R'; break;
case LLC_U_POLL: f = 'P'; break;
case LLC_GSAP|LLC_U_POLL: f = 'F'; break;
default: f = '?'; break;
}
printf("%s/%c", m, f);
p += 3;
length -= 3;
caplen -= 3;
if ((control & ~LLC_U_POLL) == LLC_XID) {
if (*p == LLC_XID_FI) {
printf(": %02x %02x", p[1], p[2]);
p += 3;
length -= 3;
caplen -= 3;
}
}
} else {
char f;
switch ((ssap & LLC_GSAP) | (control & LLC_IS_POLL)) {
case 0: f = 'C'; break;
case LLC_GSAP: f = 'R'; break;
case LLC_IS_POLL: f = 'P'; break;
case LLC_GSAP|LLC_IS_POLL: f = 'F'; break;
default: f = '?'; break;
}
if ((control & LLC_S_FMT) == LLC_S_FMT) {
static const char *llc_s[] = { "rr", "rej", "rnr", "03" };
(void)printf("%s (r=%d,%c)",
llc_s[LLC_S_CMD(control)],
LLC_IS_NR(control),
f);
} else {
(void)printf("I (s=%d,r=%d,%c)",
LLC_I_NS(control),
LLC_IS_NR(control),
f);
}
p += 4;
length -= 4;
caplen -= 4;
}
return(1);
}