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slow: Move version handling to subtype functions #1376

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5f4b040
slow: Move version handling to subtype functions
corubba Oct 19, 2025
15ada8d
fixup! slow: Move version handling to subtype functions
corubba Oct 20, 2025
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131 changes: 50 additions & 81 deletions print-slow.c
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Original file line number Diff line number Diff line change
Expand Up @@ -39,14 +39,6 @@
#define LACP_VERSION 1
#define MARKER_VERSION 1

static const struct tok slow_proto_values[] = {
{ SLOW_PROTO_LACP, "LACP" },
{ SLOW_PROTO_MARKER, "MARKER" },
{ SLOW_PROTO_OAM, "OAM" },
{ SLOW_PROTO_OSSP, "OSSP" },
{ 0, NULL}
};

static const struct tok slow_oam_flag_values[] = {
{ 0x0001, "Link Fault" },
{ 0x0002, "Dying Gasp" },
Expand Down Expand Up @@ -243,100 +235,41 @@ static void slow_marker_lacp_print(netdissect_options *, const u_char *, u_int,
static void slow_oam_print(netdissect_options *, const u_char *, u_int);
static void slow_ossp_print(netdissect_options *, const u_char *, u_int);

/*
* Print Slow Protocol. (802.3 Annex 57A)
*/
void
slow_print(netdissect_options *ndo,
const u_char *pptr, u_int len)
{
int print_version;
u_int subtype;

ndo->ndo_protocol = "slow";

if (len < 1)
goto tooshort;
subtype = GET_U_1(pptr);
len -= 1;
pptr += 1;

/*
* Sanity checking of the header.
*/
switch (subtype) {
case SLOW_PROTO_LACP:
if (len < 2)
goto tooshort;
if (GET_U_1(pptr + 1) != LACP_VERSION) {
ND_PRINT("LACP version %u packet not supported",
GET_U_1(pptr + 1));
return;
}
print_version = 1;
break;

case SLOW_PROTO_LACP: /* fall through */
case SLOW_PROTO_MARKER:
if (len < 2)
goto tooshort;
if (GET_U_1(pptr + 1) != MARKER_VERSION) {
ND_PRINT("MARKER version %u packet not supported",
GET_U_1(pptr + 1));
return;
}
print_version = 1;
slow_marker_lacp_print(ndo, pptr, len, subtype);
break;

case SLOW_PROTO_OAM:
case SLOW_PROTO_OSSP:
print_version = 0;
break;

default:
/* print basic information and exit */
print_version = -1;
break;
}

if (print_version == 1) {
ND_PRINT("%sv%u, length %u",
tok2str(slow_proto_values, "unknown (%u)", subtype),
GET_U_1((pptr + 1)),
len);
} else {
/* some slow protos don't have a version number in the header */
ND_PRINT("%s, length %u",
tok2str(slow_proto_values, "unknown (%u)", subtype),
len);
}

/* unrecognized subtype */
if (print_version == -1) {
print_unknown_data(ndo, pptr, "\n\t", len);
return;
}

if (!ndo->ndo_vflag)
return;

switch (subtype) {
default: /* should not happen */
slow_oam_print(ndo, pptr, len);
break;

case SLOW_PROTO_OSSP:
/* skip subtype */
len -= 1;
pptr += 1;
slow_ossp_print(ndo, pptr, len);
break;

case SLOW_PROTO_OAM:
/* skip subtype */
len -= 1;
pptr += 1;
slow_oam_print(ndo, pptr, len);
break;

case SLOW_PROTO_LACP: /* LACP and MARKER share the same semantics */
case SLOW_PROTO_MARKER:
/* skip subtype and version */
len -= 2;
pptr += 2;
slow_marker_lacp_print(ndo, pptr, len, subtype);
default:
ND_PRINT("unknown (%u), length %u", subtype, len + 1);
if (ndo->ndo_vflag)
print_unknown_data(ndo, pptr, "\n\t", len);
break;
}
return;
Expand All @@ -348,14 +281,17 @@ slow_print(netdissect_options *ndo,
ND_PRINT("\n\t\t packet is too short");
}

/*
* Print Link Aggregation Control Protocol and Marker protocol. (802.3ad / 802.1ax)
*/
static void
slow_marker_lacp_print(netdissect_options *ndo,
const u_char *tptr, u_int tlen,
u_int proto_subtype)
{
const struct tlv_header_t *tlv_header;
const u_char *tlv_tptr;
u_int tlv_type, tlv_len, tlv_tlen;
u_int tlv_type, tlv_len, tlv_tlen, version;

union {
const struct lacp_marker_tlv_terminator_t *lacp_marker_tlv_terminator;
Expand All @@ -364,6 +300,26 @@ slow_marker_lacp_print(netdissect_options *ndo,
const struct marker_tlv_marker_info_t *marker_tlv_marker_info;
} tlv_ptr;

if (tlen < 1)
goto tooshort;

version = GET_U_1(tptr);
tlen -= 1;
tptr += 1;

ND_PRINT("%sv%u, length %u",
proto_subtype == SLOW_PROTO_LACP ? "LACP" : "MARKER",
version, tlen + 2);

if (!ndo->ndo_vflag)
return;

if ((proto_subtype == SLOW_PROTO_LACP && version != LACP_VERSION)
|| (proto_subtype == SLOW_PROTO_MARKER && version != MARKER_VERSION)) {
print_unknown_data(ndo, tptr, "\n\t", tlen);
return;
}

while(tlen != 0) {
/* is the packet big enough to include the tlv header ? */
if (tlen < sizeof(struct tlv_header_t))
Expand Down Expand Up @@ -485,6 +441,9 @@ slow_marker_lacp_print(netdissect_options *ndo,
ND_PRINT("\n\t\t packet is too short");
}

/*
* Print Operations, Administration, and Maintenance. (802.3)
*/
static void
slow_oam_print(netdissect_options *ndo,
const u_char *tptr, u_int tlen)
Expand Down Expand Up @@ -518,6 +477,11 @@ slow_oam_print(netdissect_options *ndo,
const struct slow_oam_loopbackctrl_t *slow_oam_loopbackctrl;
} tlv;

ND_PRINT("OAM, length %u", tlen + 1);

if (!ndo->ndo_vflag)
return;

ptr.slow_oam_common_header = (const struct slow_oam_common_header_t *)tptr;
if (tlen < sizeof(*ptr.slow_oam_common_header))
goto tooshort;
Expand Down Expand Up @@ -754,6 +718,11 @@ slow_ossp_print(netdissect_options *ndo,
{
uint32_t oui;

ND_PRINT("OSSP, length %u", tlen + 1);

if (!ndo->ndo_vflag)
return;

ND_ICHECKMSG_U("length", tlen, <, 3);

oui = GET_BE_U_3(tptr);
Expand Down