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tcpdump/print-mptcp.c
Davide Caratti 1ac47641c5 mptcp: add support for MP_TCPRST 
dissect the MP_TCPRST sub-option in accordance to RFC8684 §3.6.

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/189
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
2021-07-12 10:51:58 +02:00

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/**
* Copyright (c) 2012
*
* Gregory Detal <gregory.detal@uclouvain.be>
* Christoph Paasch <christoph.paasch@uclouvain.be>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the University nor of the Laboratory may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* \summary: Multipath TCP (MPTCP) printer */
/* specification: RFC 6824 */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "netdissect-stdinc.h"
#include "netdissect.h"
#include "extract.h"
#include "addrtoname.h"
#include "tcp.h"
#define MPTCP_SUB_CAPABLE 0x0
#define MPTCP_SUB_JOIN 0x1
#define MPTCP_SUB_DSS 0x2
#define MPTCP_SUB_ADD_ADDR 0x3
#define MPTCP_SUB_REMOVE_ADDR 0x4
#define MPTCP_SUB_PRIO 0x5
#define MPTCP_SUB_FAIL 0x6
#define MPTCP_SUB_FCLOSE 0x7
#define MPTCP_SUB_TCPRST 0x8
struct mptcp_option {
nd_uint8_t kind;
nd_uint8_t len;
nd_uint8_t sub_etc; /* subtype upper 4 bits, other stuff lower 4 bits */
};
#define MPTCP_OPT_SUBTYPE(sub_etc) (((sub_etc) >> 4) & 0xF)
struct mp_capable {
nd_uint8_t kind;
nd_uint8_t len;
nd_uint8_t sub_ver;
nd_uint8_t flags;
nd_uint64_t sender_key;
nd_uint64_t receiver_key;
nd_uint16_t data_len;
};
#define MP_CAPABLE_OPT_VERSION(sub_ver) (((sub_ver) >> 0) & 0xF)
#define MP_CAPABLE_C 0x80
#define MP_CAPABLE_S 0x01
struct mp_join {
nd_uint8_t kind;
nd_uint8_t len;
nd_uint8_t sub_b;
nd_uint8_t addr_id;
union {
struct {
nd_uint32_t token;
nd_uint32_t nonce;
} syn;
struct {
nd_uint64_t mac;
nd_uint32_t nonce;
} synack;
struct {
nd_byte mac[20];
} ack;
} u;
};
#define MP_JOIN_B 0x01
struct mp_dss {
nd_uint8_t kind;
nd_uint8_t len;
nd_uint8_t sub;
nd_uint8_t flags;
};
#define MP_DSS_F 0x10
#define MP_DSS_m 0x08
#define MP_DSS_M 0x04
#define MP_DSS_a 0x02
#define MP_DSS_A 0x01
static const struct tok mptcp_addr_subecho_bits[] = {
{ 0x6, "v0-ip6" },
{ 0x4, "v0-ip4" },
{ 0x1, "v1-echo" },
{ 0x0, "v1" },
{ 0, NULL }
};
struct mp_add_addr {
nd_uint8_t kind;
nd_uint8_t len;
nd_uint8_t sub_echo;
nd_uint8_t addr_id;
union {
struct {
nd_ipv4 addr;
nd_uint16_t port;
nd_uint64_t mac;
} v4;
struct {
nd_ipv4 addr;
nd_uint64_t mac;
} v4np;
struct {
nd_ipv6 addr;
nd_uint16_t port;
nd_uint64_t mac;
} v6;
struct {
nd_ipv6 addr;
nd_uint64_t mac;
} v6np;
} u;
};
struct mp_remove_addr {
nd_uint8_t kind;
nd_uint8_t len;
nd_uint8_t sub;
/* list of addr_id */
nd_uint8_t addrs_id[1];
};
struct mp_fail {
nd_uint8_t kind;
nd_uint8_t len;
nd_uint8_t sub;
nd_uint8_t resv;
nd_uint64_t data_seq;
};
struct mp_close {
nd_uint8_t kind;
nd_uint8_t len;
nd_uint8_t sub;
nd_uint8_t rsv;
nd_byte key[8];
};
struct mp_prio {
nd_uint8_t kind;
nd_uint8_t len;
nd_uint8_t sub_b;
nd_uint8_t addr_id;
};
#define MP_PRIO_B 0x01
static const struct tok mp_tcprst_flags[] = {
{ 0x08, "U" },
{ 0x04, "V" },
{ 0x02, "W" },
{ 0x01, "T" },
{ 0, NULL }
};
static const struct tok mp_tcprst_reasons[] = {
{ 0x06, "Middlebox interference" },
{ 0x05, "Unacceptable performance" },
{ 0x04, "Too much outstanding data" },
{ 0x03, "Administratively prohibited" },
{ 0x02, "Lack of resources" },
{ 0x01, "MPTCP-specific error" },
{ 0x00, "Unspecified error" },
{ 0, NULL }
};
struct mp_tcprst {
nd_uint8_t kind;
nd_uint8_t len;
nd_uint8_t sub_b;
nd_uint8_t reason;
};
static int
dummy_print(netdissect_options *ndo _U_,
const u_char *opt _U_, u_int opt_len _U_, u_char flags _U_)
{
return 1;
}
static int
mp_capable_print(netdissect_options *ndo,
const u_char *opt, u_int opt_len, u_char flags)
{
const struct mp_capable *mpc = (const struct mp_capable *) opt;
uint8_t version, csum_enabled;
if (!((opt_len == 12 || opt_len == 4) && flags & TH_SYN) &&
!((opt_len == 20 || opt_len == 22 || opt_len == 24) && (flags & (TH_SYN | TH_ACK)) ==
TH_ACK))
return 0;
version = MP_CAPABLE_OPT_VERSION(GET_U_1(mpc->sub_ver));
switch (version) {
case 0: /* fall through */
case 1:
ND_PRINT(" v%u", version);
break;
default:
ND_PRINT(" Unknown Version (%u)", version);
return 1;
}
csum_enabled = GET_U_1(mpc->flags) & MP_CAPABLE_C;
if (csum_enabled)
ND_PRINT(" csum");
if (opt_len == 12 || opt_len >= 20) {
ND_PRINT(" {0x%" PRIx64, GET_BE_U_8(mpc->sender_key));
if (opt_len >= 20)
ND_PRINT(",0x%" PRIx64, GET_BE_U_8(mpc->receiver_key));
/* RFC 8684 Section 3.1 */
if ((opt_len == 22 && !csum_enabled) || opt_len == 24)
ND_PRINT(",data_len=%u", GET_BE_U_2(mpc->data_len));
ND_PRINT("}");
}
return 1;
}
static int
mp_join_print(netdissect_options *ndo,
const u_char *opt, u_int opt_len, u_char flags)
{
const struct mp_join *mpj = (const struct mp_join *) opt;
if (!(opt_len == 12 && (flags & TH_SYN)) &&
!(opt_len == 16 && (flags & (TH_SYN | TH_ACK)) == (TH_SYN | TH_ACK)) &&
!(opt_len == 24 && (flags & TH_ACK)))
return 0;
if (opt_len != 24) {
if (GET_U_1(mpj->sub_b) & MP_JOIN_B)
ND_PRINT(" backup");
ND_PRINT(" id %u", GET_U_1(mpj->addr_id));
}
switch (opt_len) {
case 12: /* SYN */
ND_PRINT(" token 0x%x" " nonce 0x%x",
GET_BE_U_4(mpj->u.syn.token),
GET_BE_U_4(mpj->u.syn.nonce));
break;
case 16: /* SYN/ACK */
ND_PRINT(" hmac 0x%" PRIx64 " nonce 0x%x",
GET_BE_U_8(mpj->u.synack.mac),
GET_BE_U_4(mpj->u.synack.nonce));
break;
case 24: {/* ACK */
size_t i;
ND_PRINT(" hmac 0x");
for (i = 0; i < sizeof(mpj->u.ack.mac); ++i)
ND_PRINT("%02x", mpj->u.ack.mac[i]);
}
default:
break;
}
return 1;
}
static int
mp_dss_print(netdissect_options *ndo,
const u_char *opt, u_int opt_len, u_char flags)
{
const struct mp_dss *mdss = (const struct mp_dss *) opt;
uint8_t mdss_flags;
/* We need the flags, at a minimum. */
if (opt_len < 4)
return 0;
if (flags & TH_SYN)
return 0;
mdss_flags = GET_U_1(mdss->flags);
if (mdss_flags & MP_DSS_F)
ND_PRINT(" fin");
opt += 4;
opt_len -= 4;
if (mdss_flags & MP_DSS_A) {
/* Ack present */
ND_PRINT(" ack ");
/*
* If the a flag is set, we have an 8-byte ack; if it's
* clear, we have a 4-byte ack.
*/
if (mdss_flags & MP_DSS_a) {
if (opt_len < 8)
return 0;
ND_PRINT("%" PRIu64, GET_BE_U_8(opt));
opt += 8;
opt_len -= 8;
} else {
if (opt_len < 4)
return 0;
ND_PRINT("%u", GET_BE_U_4(opt));
opt += 4;
opt_len -= 4;
}
}
if (mdss_flags & MP_DSS_M) {
/*
* Data Sequence Number (DSN), Subflow Sequence Number (SSN),
* Data-Level Length present, and Checksum possibly present.
*/
ND_PRINT(" seq ");
/*
* If the m flag is set, we have an 8-byte NDS; if it's clear,
* we have a 4-byte DSN.
*/
if (mdss_flags & MP_DSS_m) {
if (opt_len < 8)
return 0;
ND_PRINT("%" PRIu64, GET_BE_U_8(opt));
opt += 8;
opt_len -= 8;
} else {
if (opt_len < 4)
return 0;
ND_PRINT("%u", GET_BE_U_4(opt));
opt += 4;
opt_len -= 4;
}
if (opt_len < 4)
return 0;
ND_PRINT(" subseq %u", GET_BE_U_4(opt));
opt += 4;
opt_len -= 4;
if (opt_len < 2)
return 0;
ND_PRINT(" len %u", GET_BE_U_2(opt));
opt += 2;
opt_len -= 2;
/*
* The Checksum is present only if negotiated.
* If there are at least 2 bytes left, process the next 2
* bytes as the Checksum.
*/
if (opt_len >= 2) {
ND_PRINT(" csum 0x%x", GET_BE_U_2(opt));
opt_len -= 2;
}
}
if (opt_len != 0)
return 0;
return 1;
}
static int
add_addr_print(netdissect_options *ndo,
const u_char *opt, u_int opt_len, u_char flags _U_)
{
const struct mp_add_addr *add_addr = (const struct mp_add_addr *) opt;
if (!(opt_len == 8 || opt_len == 10 || opt_len == 16 || opt_len == 18 ||
opt_len == 20 || opt_len == 22 || opt_len == 28 || opt_len == 30))
return 0;
ND_PRINT(" %s",
tok2str(mptcp_addr_subecho_bits, "[bad version/echo]",
GET_U_1(add_addr->sub_echo) & 0xF));
ND_PRINT(" id %u", GET_U_1(add_addr->addr_id));
if (opt_len == 8 || opt_len == 10 || opt_len == 16 || opt_len == 18) {
ND_PRINT(" %s", GET_IPADDR_STRING(add_addr->u.v4.addr));
if (opt_len == 10 || opt_len == 18)
ND_PRINT(":%u", GET_BE_U_2(add_addr->u.v4.port));
if (opt_len == 16)
ND_PRINT(" hmac 0x%" PRIx64, GET_BE_U_8(add_addr->u.v4np.mac));
if (opt_len == 18)
ND_PRINT(" hmac 0x%" PRIx64, GET_BE_U_8(add_addr->u.v4.mac));
}
if (opt_len == 20 || opt_len == 22 || opt_len == 28 || opt_len == 30) {
ND_PRINT(" %s", GET_IP6ADDR_STRING(add_addr->u.v6.addr));
if (opt_len == 22 || opt_len == 30)
ND_PRINT(":%u", GET_BE_U_2(add_addr->u.v6.port));
if (opt_len == 28)
ND_PRINT(" hmac 0x%" PRIx64, GET_BE_U_8(add_addr->u.v6np.mac));
if (opt_len == 30)
ND_PRINT(" hmac 0x%" PRIx64, GET_BE_U_8(add_addr->u.v6.mac));
}
return 1;
}
static int
remove_addr_print(netdissect_options *ndo,
const u_char *opt, u_int opt_len, u_char flags _U_)
{
const struct mp_remove_addr *remove_addr = (const struct mp_remove_addr *) opt;
u_int i;
if (opt_len < 4)
return 0;
opt_len -= 3;
ND_PRINT(" id");
for (i = 0; i < opt_len; i++)
ND_PRINT(" %u", GET_U_1(remove_addr->addrs_id[i]));
return 1;
}
static int
mp_prio_print(netdissect_options *ndo,
const u_char *opt, u_int opt_len, u_char flags _U_)
{
const struct mp_prio *mpp = (const struct mp_prio *) opt;
if (opt_len != 3 && opt_len != 4)
return 0;
if (GET_U_1(mpp->sub_b) & MP_PRIO_B)
ND_PRINT(" backup");
else
ND_PRINT(" non-backup");
if (opt_len == 4)
ND_PRINT(" id %u", GET_U_1(mpp->addr_id));
return 1;
}
static int
mp_fail_print(netdissect_options *ndo,
const u_char *opt, u_int opt_len, u_char flags _U_)
{
if (opt_len != 12)
return 0;
ND_PRINT(" seq %" PRIu64, GET_BE_U_8(opt + 4));
return 1;
}
static int
mp_fast_close_print(netdissect_options *ndo,
const u_char *opt, u_int opt_len, u_char flags _U_)
{
if (opt_len != 12)
return 0;
ND_PRINT(" key 0x%" PRIx64, GET_BE_U_8(opt + 4));
return 1;
}
static int
mp_tcprst_print(netdissect_options *ndo,
const u_char *opt, u_int opt_len, u_char flags _U_)
{
const struct mp_tcprst *mpr = (const struct mp_tcprst *)opt;
if (opt_len != 4)
return 0;
ND_PRINT(" flags [%s]", bittok2str_nosep(mp_tcprst_flags, "none",
GET_U_1(mpr->sub_b)));
ND_PRINT(" reason %s", tok2str(mp_tcprst_reasons, "unknown (0x%02x)",
GET_U_1(mpr->reason)));
return 1;
}
static const struct {
const char *name;
int (*print)(netdissect_options *, const u_char *, u_int, u_char);
} mptcp_options[] = {
{ "capable", mp_capable_print },
{ "join", mp_join_print },
{ "dss", mp_dss_print },
{ "add-addr", add_addr_print },
{ "rem-addr", remove_addr_print },
{ "prio", mp_prio_print },
{ "fail", mp_fail_print },
{ "fast-close", mp_fast_close_print },
{ "tcprst", mp_tcprst_print },
{ "unknown", dummy_print },
};
int
mptcp_print(netdissect_options *ndo,
const u_char *cp, u_int len, u_char flags)
{
const struct mptcp_option *opt;
u_int subtype;
ndo->ndo_protocol = "mptcp";
if (len < 3)
return 0;
opt = (const struct mptcp_option *) cp;
subtype = MPTCP_OPT_SUBTYPE(GET_U_1(opt->sub_etc));
subtype = ND_MIN(subtype, MPTCP_SUB_TCPRST + 1);
ND_PRINT(" %u", len);
ND_PRINT(" %s", mptcp_options[subtype].name);
return mptcp_options[subtype].print(ndo, cp, len, flags);
}
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