Merge branch 'tc-mpls-action' into next

John Hurley  says:

====================

Recent kernel additions to TC allows the manipulation of MPLS headers as
filter actions.

The following patchset creates an iproute2 interface to the new actions
and includes documentation on how to use it.

v1->v2:
- change error from print_string() to fprintf(strerr,) (Stephen Hemminger)
- split long line in explain() message (David Ahern)
- use _SL_ instead of /n in print message (David Ahern)

====================

Signed-off-by: David Ahern <dsahern@gmail.com>
This commit is contained in:
David Ahern 2019-07-10 14:07:42 -07:00
commit 25c567bdcd
5 changed files with 468 additions and 0 deletions

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@ -0,0 +1,33 @@
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/* Copyright (C) 2019 Netronome Systems, Inc. */
#ifndef __LINUX_TC_MPLS_H
#define __LINUX_TC_MPLS_H
#include <linux/pkt_cls.h>
#define TCA_MPLS_ACT_POP 1
#define TCA_MPLS_ACT_PUSH 2
#define TCA_MPLS_ACT_MODIFY 3
#define TCA_MPLS_ACT_DEC_TTL 4
struct tc_mpls {
tc_gen; /* generic TC action fields. */
int m_action; /* action of type TCA_MPLS_ACT_*. */
};
enum {
TCA_MPLS_UNSPEC,
TCA_MPLS_TM, /* struct tcf_t; time values associated with action. */
TCA_MPLS_PARMS, /* struct tc_mpls; action type and general TC fields. */
TCA_MPLS_PAD,
TCA_MPLS_PROTO, /* be16; eth_type of pushed or next (for pop) header. */
TCA_MPLS_LABEL, /* u32; MPLS label. Lower 20 bits are used. */
TCA_MPLS_TC, /* u8; MPLS TC field. Lower 3 bits are used. */
TCA_MPLS_TTL, /* u8; MPLS TTL field. Must not be 0. */
TCA_MPLS_BOS, /* u8; MPLS BOS field. Either 1 or 0. */
__TCA_MPLS_MAX,
};
#define TCA_MPLS_MAX (__TCA_MPLS_MAX - 1)
#endif

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@ -78,6 +78,8 @@ __PF(TIPC,tipc)
__PF(AOE,aoe) __PF(AOE,aoe)
__PF(8021Q,802.1Q) __PF(8021Q,802.1Q)
__PF(8021AD,802.1ad) __PF(8021AD,802.1ad)
__PF(MPLS_UC,mpls_uc)
__PF(MPLS_MC,mpls_mc)
{ 0x8100, "802.1Q" }, { 0x8100, "802.1Q" },
{ 0x88cc, "LLDP" }, { 0x88cc, "LLDP" },

156
man/man8/tc-mpls.8 Normal file
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@ -0,0 +1,156 @@
.TH "MPLS manipulation action in tc" 8 "22 May 2019" "iproute2" "Linux"
.SH NAME
mpls - mpls manipulation module
.SH SYNOPSIS
.in +8
.ti -8
.BR tc " ... " "action mpls" " { "
.IR POP " | " PUSH " | " MODIFY " | "
.BR dec_ttl " } [ "
.IR CONTROL " ]"
.ti -8
.IR POP " := "
.BR pop " " protocol
.IR MPLS_PROTO
.ti -8
.IR PUSH " := "
.BR push " [ " protocol
.IR MPLS_PROTO " ]"
.RB " [ " tc
.IR MPLS_TC " ] "
.RB " [ " ttl
.IR MPLS_TTL " ] "
.RB " [ " bos
.IR MPLS_BOS " ] "
.BI label " MPLS_LABEL"
.ti -8
.IR MODIFY " := "
.BR modify " [ " label
.IR MPLS_LABEL " ]"
.RB " [ " tc
.IR MPLS_TC " ] "
.RB " [ " ttl
.IR MPLS_TTL " ] "
.ti -8
.IR CONTROL " := { "
.BR reclassify " | " pipe " | " drop " | " continue " | " pass " | " goto " " chain " " CHAIN_INDEX " }"
.SH DESCRIPTION
The
.B mpls
action performs mpls encapsulation or decapsulation on a packet, reflected by the
operation modes
.IR POP ", " PUSH ", " MODIFY " and " DEC_TTL .
The
.I POP
mode requires the ethertype of the header that follows the MPLS header (e.g.
IPv4 or another MPLS). It will remove the outer MPLS header and replace the
ethertype in the MAC header with that passed. The
.IR PUSH " and " MODIFY
modes update the current MPLS header information or add a new header.
.IR PUSH
requires at least an
.IR MPLS_LABEL ". "
.I DEC_TTL
requires no arguments and simply subtracts 1 from the MPLS header TTL field.
.SH OPTIONS
.TP
.B pop
Decapsulation mode. Requires the protocol of the next header.
.TP
.B push
Encapsulation mode. Requires at least the
.B label
option.
.TP
.B modify
Replace mode. Existing MPLS tag is replaced.
.BR label ", "
.BR tc ", "
and
.B ttl
are all optional.
.TP
.B dec_ttl
Decrement the TTL field on the outer most MPLS header.
.TP
.BI label " MPLS_LABEL"
Specify the MPLS LABEL for the outer MPLS header.
.I MPLS_LABEL
is an unsigned 20bit integer, the format is detected automatically (e.g. prefix
with
.RB ' 0x '
for hexadecimal interpretation, etc.).
.TP
.BI protocol " MPLS_PROTO"
Choose the protocol to use. For push actions this must be
.BR mpls_uc " or " mpls_mc " (" mpls_uc
is the default). For pop actions it should be the protocol of the next header.
This option cannot be used with modify.
.TP
.BI tc " MPLS_TC"
Choose the TC value for the outer MPLS header. Decimal number in range of 0-7.
Defaults to 0.
.TP
.BI ttl " MPLS_TTL"
Choose the TTL value for the outer MPLS header. Number in range of 0-255. A
non-zero default value will be selected if this is not explicitly set.
.TP
.BI bos " MPLS_BOS"
Manually configure the bottom of stack bit for an MPLS header push. The default
is for TC to automatically set (or unset) the bit based on the next header of
the packet.
.TP
.I CONTROL
How to continue after executing this action.
.RS
.TP
.B reclassify
Restarts classification by jumping back to the first filter attached to this
action's parent.
.TP
.B pipe
Continue with the next action, this is the default.
.TP
.B drop
Packet will be dropped without running further actions.
.TP
.B continue
Continue classification with next filter in line.
.TP
.B pass
Return to calling qdisc for packet processing. This ends the classification
process.
.RE
.SH EXAMPLES
The following example encapsulates incoming IP packets on eth0 into MPLS with
a label 123 and sends them out eth1:
.RS
.EX
#tc qdisc add dev eth0 handle ffff: ingress
#tc filter add dev eth0 protocol ip parent ffff: flower \\
action mpls push protocol mpls_uc label 123 \\
action mirred egress redirect dev eth1
.EE
.RE
In this example, incoming MPLS unicast packets on eth0 are decapsulated and to
ip packets and output to eth1:
.RS
.EX
#tc qdisc add dev eth0 handle ffff: ingress
#tc filter add dev eth0 protocol mpls_uc parent ffff: flower \\
action mpls pop protocol ipv4 \\
action mirred egress redirect dev eth0
.EE
.RE
.SH SEE ALSO
.BR tc (8)

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@ -39,6 +39,7 @@ TCMODULES += q_drr.o
TCMODULES += q_qfq.o TCMODULES += q_qfq.o
TCMODULES += m_gact.o TCMODULES += m_gact.o
TCMODULES += m_mirred.o TCMODULES += m_mirred.o
TCMODULES += m_mpls.o
TCMODULES += m_nat.o TCMODULES += m_nat.o
TCMODULES += m_pedit.o TCMODULES += m_pedit.o
TCMODULES += m_ife.o TCMODULES += m_ife.o

276
tc/m_mpls.c Normal file
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@ -0,0 +1,276 @@
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2019 Netronome Systems, Inc. */
#include <linux/if_ether.h>
#include <linux/tc_act/tc_mpls.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "utils.h"
#include "rt_names.h"
#include "tc_util.h"
static const char * const action_names[] = {
[TCA_MPLS_ACT_POP] = "pop",
[TCA_MPLS_ACT_PUSH] = "push",
[TCA_MPLS_ACT_MODIFY] = "modify",
[TCA_MPLS_ACT_DEC_TTL] = "dec_ttl",
};
static void explain(void)
{
fprintf(stderr,
"Usage: mpls pop [ protocol MPLS_PROTO ]\n"
" mpls push [ protocol MPLS_PROTO ] [ label MPLS_LABEL ] [ tc MPLS_TC ]\n"
" [ ttl MPLS_TTL ] [ bos MPLS_BOS ] [CONTROL]\n"
" mpls modify [ label MPLS_LABEL ] [ tc MPLS_TC ] [ ttl MPLS_TTL ] [CONTROL]\n"
" for pop MPLS_PROTO is next header of packet - e.g. ip or mpls_uc\n"
" for push MPLS_PROTO is one of mpls_uc or mpls_mc\n"
" with default: mpls_uc\n"
" CONTROL := reclassify | pipe | drop | continue | pass |\n"
" goto chain <CHAIN_INDEX>\n");
}
static void usage(void)
{
explain();
exit(-1);
}
static bool can_modify_mpls_fields(unsigned int action)
{
return action == TCA_MPLS_ACT_PUSH || action == TCA_MPLS_ACT_MODIFY;
}
static bool can_modify_ethtype(unsigned int action)
{
return action == TCA_MPLS_ACT_PUSH || action == TCA_MPLS_ACT_POP;
}
static bool is_valid_label(__u32 label)
{
return label <= 0xfffff;
}
static bool check_double_action(unsigned int action, const char *arg)
{
if (!action)
return false;
fprintf(stderr,
"Error: got \"%s\" but action already set to \"%s\"\n",
arg, action_names[action]);
explain();
return true;
}
static int parse_mpls(struct action_util *a, int *argc_p, char ***argv_p,
int tca_id, struct nlmsghdr *n)
{
struct tc_mpls parm = {};
__u32 label = 0xffffffff;
unsigned int action = 0;
char **argv = *argv_p;
struct rtattr *tail;
int argc = *argc_p;
__u16 proto = 0;
__u8 bos = 0xff;
__u8 tc = 0xff;
__u8 ttl = 0;
if (matches(*argv, "mpls") != 0)
return -1;
NEXT_ARG();
while (argc > 0) {
if (matches(*argv, "pop") == 0) {
if (check_double_action(action, *argv))
return -1;
action = TCA_MPLS_ACT_POP;
} else if (matches(*argv, "push") == 0) {
if (check_double_action(action, *argv))
return -1;
action = TCA_MPLS_ACT_PUSH;
} else if (matches(*argv, "modify") == 0) {
if (check_double_action(action, *argv))
return -1;
action = TCA_MPLS_ACT_MODIFY;
} else if (matches(*argv, "dec_ttl") == 0) {
if (check_double_action(action, *argv))
return -1;
action = TCA_MPLS_ACT_DEC_TTL;
} else if (matches(*argv, "label") == 0) {
if (!can_modify_mpls_fields(action))
invarg("only valid for push/modify", *argv);
NEXT_ARG();
if (get_u32(&label, *argv, 0) || !is_valid_label(label))
invarg("label must be <=0xFFFFF", *argv);
} else if (matches(*argv, "tc") == 0) {
if (!can_modify_mpls_fields(action))
invarg("only valid for push/modify", *argv);
NEXT_ARG();
if (get_u8(&tc, *argv, 0) || (tc & ~0x7))
invarg("tc field is 3 bits max", *argv);
} else if (matches(*argv, "ttl") == 0) {
if (!can_modify_mpls_fields(action))
invarg("only valid for push/modify", *argv);
NEXT_ARG();
if (get_u8(&ttl, *argv, 0) || !ttl)
invarg("ttl must be >0 and <=255", *argv);
} else if (matches(*argv, "bos") == 0) {
if (!can_modify_mpls_fields(action))
invarg("only valid for push/modify", *argv);
NEXT_ARG();
if (get_u8(&bos, *argv, 0) || (bos & ~0x1))
invarg("bos must be 0 or 1", *argv);
} else if (matches(*argv, "protocol") == 0) {
if (!can_modify_ethtype(action))
invarg("only valid for push/pop", *argv);
NEXT_ARG();
if (ll_proto_a2n(&proto, *argv))
invarg("protocol is invalid", *argv);
} else if (matches(*argv, "help") == 0) {
usage();
} else {
break;
}
NEXT_ARG_FWD();
}
if (!action)
incomplete_command();
parse_action_control_dflt(&argc, &argv, &parm.action,
false, TC_ACT_PIPE);
if (argc) {
if (matches(*argv, "index") == 0) {
NEXT_ARG();
if (get_u32(&parm.index, *argv, 10))
invarg("illegal index", *argv);
NEXT_ARG_FWD();
}
}
if (action == TCA_MPLS_ACT_PUSH && !label)
missarg("label");
if (action == TCA_MPLS_ACT_PUSH && proto &&
proto != htons(ETH_P_MPLS_UC) && proto != htons(ETH_P_MPLS_MC)) {
fprintf(stderr,
"invalid push protocol \"0x%04x\" - use mpls_(uc|mc)\n",
ntohs(proto));
return -1;
}
if (action == TCA_MPLS_ACT_POP && !proto)
missarg("protocol");
parm.m_action = action;
tail = addattr_nest(n, MAX_MSG, tca_id | NLA_F_NESTED);
addattr_l(n, MAX_MSG, TCA_MPLS_PARMS, &parm, sizeof(parm));
if (label != 0xffffffff)
addattr_l(n, MAX_MSG, TCA_MPLS_LABEL, &label, sizeof(label));
if (proto)
addattr_l(n, MAX_MSG, TCA_MPLS_PROTO, &proto, sizeof(proto));
if (tc != 0xff)
addattr8(n, MAX_MSG, TCA_MPLS_TC, tc);
if (ttl)
addattr8(n, MAX_MSG, TCA_MPLS_TTL, ttl);
if (bos != 0xff)
addattr8(n, MAX_MSG, TCA_MPLS_BOS, bos);
addattr_nest_end(n, tail);
*argc_p = argc;
*argv_p = argv;
return 0;
}
static int print_mpls(struct action_util *au, FILE *f, struct rtattr *arg)
{
struct rtattr *tb[TCA_MPLS_MAX + 1];
struct tc_mpls *parm;
SPRINT_BUF(b1);
__u32 val;
if (!arg)
return -1;
parse_rtattr_nested(tb, TCA_MPLS_MAX, arg);
if (!tb[TCA_MPLS_PARMS]) {
fprintf(stderr, "[NULL mpls parameters]\n");
return -1;
}
parm = RTA_DATA(tb[TCA_MPLS_PARMS]);
print_string(PRINT_ANY, "kind", "%s ", "mpls");
print_string(PRINT_ANY, "mpls_action", " %s",
action_names[parm->m_action]);
switch (parm->m_action) {
case TCA_MPLS_ACT_POP:
if (tb[TCA_MPLS_PROTO]) {
__u16 proto;
proto = rta_getattr_u16(tb[TCA_MPLS_PROTO]);
print_string(PRINT_ANY, "protocol", " protocol %s",
ll_proto_n2a(proto, b1, sizeof(b1)));
}
break;
case TCA_MPLS_ACT_PUSH:
if (tb[TCA_MPLS_PROTO]) {
__u16 proto;
proto = rta_getattr_u16(tb[TCA_MPLS_PROTO]);
print_string(PRINT_ANY, "protocol", " protocol %s",
ll_proto_n2a(proto, b1, sizeof(b1)));
}
/* Fallthrough */
case TCA_MPLS_ACT_MODIFY:
if (tb[TCA_MPLS_LABEL]) {
val = rta_getattr_u32(tb[TCA_MPLS_LABEL]);
print_uint(PRINT_ANY, "label", " label %u", val);
}
if (tb[TCA_MPLS_TC]) {
val = rta_getattr_u8(tb[TCA_MPLS_TC]);
print_uint(PRINT_ANY, "tc", " tc %u", val);
}
if (tb[TCA_MPLS_BOS]) {
val = rta_getattr_u8(tb[TCA_MPLS_BOS]);
print_uint(PRINT_ANY, "bos", " bos %u", val);
}
if (tb[TCA_MPLS_TTL]) {
val = rta_getattr_u8(tb[TCA_MPLS_TTL]);
print_uint(PRINT_ANY, "ttl", " ttl %u", val);
}
break;
}
print_action_control(f, " ", parm->action, "");
print_uint(PRINT_ANY, "index", "\n\t index %u", parm->index);
print_int(PRINT_ANY, "ref", " ref %d", parm->refcnt);
print_int(PRINT_ANY, "bind", " bind %d", parm->bindcnt);
if (show_stats) {
if (tb[TCA_MPLS_TM]) {
struct tcf_t *tm = RTA_DATA(tb[TCA_MPLS_TM]);
print_tm(f, tm);
}
}
print_string(PRINT_FP, NULL, "%s", _SL_);
return 0;
}
struct action_util mpls_action_util = {
.id = "mpls",
.parse_aopt = parse_mpls,
.print_aopt = print_mpls,
};