xref: /dragonfly/sys/netproto/mpls/mpls_input.c (revision e293de53)
1 /*
2  * Copyright (c) 2007 The DragonFly Project.  All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in
12  *    the documentation and/or other materials provided with the
13  *    distribution.
14  * 3. Neither the name of The DragonFly Project nor the names of its
15  *    contributors may be used to endorse or promote products derived
16  *    from this software without specific, prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
22  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
28  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  * $DragonFly: src/sys/netproto/mpls/mpls_input.c,v 1.4 2008/09/24 14:26:39 sephe Exp $
32  */
33 
34 #include <sys/globaldata.h>
35 #include <sys/kernel.h>
36 #include <sys/mbuf.h>
37 #include <sys/param.h>
38 #include <sys/sysctl.h>
39 #include <sys/systm.h>
40 
41 #include <net/if_var.h>
42 #include <net/netisr.h>
43 #include <net/route.h>
44 
45 #include <netproto/mpls/mpls.h>
46 #include <netproto/mpls/mpls_var.h>
47 
48 struct mpls_stats	mplsstats_percpu[MAXCPU];
49 struct route		mplsforward_rt[MAXCPU];
50 
51 int mplsforwarding = 1;
52 /*
53 SYSCTL_INT(_net_mpls, OID_AUTO, forwarding, CTLFLAG_RW,
54     &mplsforwarding, 0, "Enable MPLS forwarding between interfaces");
55 */
56 
57 static void	mpls_input_handler(struct netmsg *);
58 static void	mpls_forward(struct mbuf *);
59 
60 void
61 mpls_init(void)
62 {
63 #ifdef SMP
64 	int cpu;
65 #endif
66 
67 	/*
68 	 * Initialize MPLS statistics counters for each CPU.
69 	 *
70 	 */
71 #ifdef SMP
72 	for (cpu = 0; cpu < ncpus; ++cpu) {
73 		bzero(&mplsstats_percpu[cpu], sizeof(struct mpls_stats));
74 	}
75 #else
76 	bzero(&mplsstat, sizeof(struct mpls_stats));
77 #endif
78 
79 	netisr_register(NETISR_MPLS, mpls_mport, pktinfo_portfn_notsupp,
80 			mpls_input_handler, NETISR_FLAG_NOTMPSAFE);
81 }
82 
83 static void
84 mpls_input_handler(struct netmsg *msg0)
85 {
86         struct mbuf *m = ((struct netmsg_packet *)msg0)->nm_packet;
87 
88         mpls_input(m);
89 }
90 
91 void
92 mpls_input(struct mbuf *m)
93 {
94 	struct mpls *mpls = NULL;
95 	mpls_label_t label;
96 
97 	M_ASSERTPKTHDR(m);
98 
99 	mplsstat.mplss_total++;
100 
101 	/* length checks already performed at mpls_demux() */
102 	KASSERT(m->m_pkthdr.len >= sizeof(struct mpls),
103 	    ("mpls_input: mpls header too small"));
104 
105 again:
106 	if (m->m_len < sizeof(struct mpls)) {
107 		m = m_pullup(m, sizeof(struct mpls));
108 		if (m == NULL) {
109 			mplsstat.mplss_toosmall++;
110 			return;
111 		}
112 	}
113 
114 	mpls = mtod(m, struct mpls*);
115 	label = MPLS_LABEL(ntohl(mpls->mpls_shim));
116 	switch (label) {
117 	case 0:
118 		/*
119 		 * Label 0: represents "IPv4 Explicit NULL Label".
120 		 */
121 		if (MPLS_STACK(ntohl(mpls->mpls_shim))) {
122 			/* Decapsulate the ip datagram from the mpls frame. */
123 			m_adj(m, sizeof(struct mpls));
124 /*
125 			ip_input(m);
126 */
127 			netisr_dispatch(NETISR_IP, m);
128 			return;
129 		}
130 		goto again; /* If not the bottom label, per RFC4182. */
131 
132 	case 1:
133 		/*
134 		 * Label 1: represents "Router Alert Label" and is valid
135 		 * anywhere except at the bottom of the stack.
136 		 */
137 		break;
138 
139 	case 2:
140 		/*
141 		 * Label 2: represents "IPv6 Explicit NULL Label".
142 		 */
143 		if (MPLS_STACK(ntohl(mpls->mpls_shim))) {
144 			/* Decapsulate the ip datagram from the mpls frame. */
145 			m_adj(m, sizeof(struct mpls));
146 			netisr_dispatch(NETISR_IPV6, m);
147 			return;
148 		}
149 		goto again; /* If not the bottom label, per RFC4182. */
150 
151 	case 3:
152 		/*
153 		 * Label 3: represents the "Implicit NULL Label" and must not
154 		 * appear on the wire.
155 		 */
156 		break;
157 	default:
158 		/*
159 		 * Labels 4 - 15: reserved, drop them.
160 		 */
161 		if (label <= 15) {
162 			mplsstat.mplss_reserved++;
163 			m_freem(m);
164 			return;
165 		}
166 		if (mplsforwarding) {
167 			mpls_forward(m);
168 			return;
169 		} else {
170 			mplsstat.mplss_cantforward++;
171 			m_freem(m);
172 			return;
173 		}
174 	}
175 
176 	mplsstat.mplss_invalid++;
177 	m_freem(m);
178 }
179 
180 static void
181 mpls_forward(struct mbuf *m)
182 {
183 	struct sockaddr_mpls *smpls;
184 	struct mpls *mpls;
185 	struct route *cache_rt = &mplsforward_rt[mycpuid];
186 	mpls_label_t label;
187 	struct ifnet *ifp;
188 	struct sockaddr *dst;
189 	int error;
190 
191 	KASSERT(m->m_len >= sizeof(struct mpls),
192 	    ("mpls_forward: mpls header not in one mbuf"));
193 
194 	mpls = mtod(m, struct mpls *);
195 	label = MPLS_LABEL(ntohl(mpls->mpls_shim));
196 
197 	smpls = (struct sockaddr_mpls *) &cache_rt->ro_dst;
198 	if (cache_rt->ro_rt == NULL || smpls->smpls_label != label) {
199 		if (cache_rt->ro_rt != NULL) {
200 			RTFREE(cache_rt->ro_rt);
201 			cache_rt->ro_rt = NULL;
202 		}
203 		smpls->smpls_family = AF_MPLS;
204 		smpls->smpls_len = sizeof(struct sockaddr_mpls);
205 		smpls->smpls_label = htonl(label);
206 		rtalloc(cache_rt);
207 		if (cache_rt->ro_rt == NULL) {
208 			/* route not found */
209 			return;
210 		}
211 	}
212 
213 	ifp = cache_rt->ro_rt->rt_ifp;
214 	dst = cache_rt->ro_rt->rt_gateway;
215 	error = mpls_output(m, cache_rt->ro_rt);
216 	if (error)
217 		goto bad;
218 	error = (*ifp->if_output)(ifp, m, dst, cache_rt->ro_rt);
219 	if (error)
220 		goto bad;
221 	mplsstat.mplss_forwarded++;
222 
223 	return;
224 bad:
225 	m_freem(m);
226 }
227