1 /*-
2 * Copyright (c) 1990, 1991 Regents of The University of Michigan.
3 * All Rights Reserved.
4 *
5 * Permission to use, copy, modify, and distribute this software and
6 * its documentation for any purpose and without fee is hereby granted,
7 * provided that the above copyright notice appears in all copies and
8 * that both that copyright notice and this permission notice appear
9 * in supporting documentation, and that the name of The University
10 * of Michigan not be used in advertising or publicity pertaining to
11 * distribution of the software without specific, written prior
12 * permission. This software is supplied as is without expressed or
13 * implied warranties of any kind.
14 *
15 * Research Systems Unix Group
16 * The University of Michigan
17 * c/o Mike Clark
18 * 535 W. William Street
19 * Ann Arbor, Michigan
20 * +1-313-763-0525
21 * netatalk@itd.umich.edu
22 */
23
24 /* $FreeBSD: src/sys/netatalk/ddp_output.c,v 1.32 2007/11/20 18:50:54 rwatson Exp $ */
25
26 #include "opt_mac.h"
27
28 #include <sys/param.h>
29 #include <sys/systm.h>
30 #include <sys/mbuf.h>
31 #include <sys/socket.h>
32 #include <sys/socketvar.h>
33
34 #include <net/if.h>
35 #include <net/route.h>
36
37 #undef s_net
38
39 #include <netatalk/at.h>
40 #include <netatalk/at_var.h>
41 #include <netatalk/ddp.h>
42 #include <netatalk/ddp_var.h>
43 #include <netatalk/at_extern.h>
44
45 #include <security/mac/mac_framework.h>
46
47 int ddp_cksum = 1;
48
49 int
50 ddp_output(struct mbuf *m, struct socket *so)
51 {
52 struct ddpehdr *deh;
53 struct ddpcb *ddp = sotoddpcb(so);
54
55 #ifdef MAC
56 SOCK_LOCK(so);
57 mac_socket_create_mbuf(so, m);
58 SOCK_UNLOCK(so);
59 #endif
60
61 M_PREPEND(m, sizeof(struct ddpehdr), M_DONTWAIT);
62 if (m == NULL)
63 return (ENOBUFS);
64
65 deh = mtod(m, struct ddpehdr *);
66 deh->deh_pad = 0;
67 deh->deh_hops = 0;
68
69 deh->deh_len = m->m_pkthdr.len;
70
71 deh->deh_dnet = ddp->ddp_fsat.sat_addr.s_net;
72 deh->deh_dnode = ddp->ddp_fsat.sat_addr.s_node;
73 deh->deh_dport = ddp->ddp_fsat.sat_port;
74 deh->deh_snet = ddp->ddp_lsat.sat_addr.s_net;
75 deh->deh_snode = ddp->ddp_lsat.sat_addr.s_node;
76 deh->deh_sport = ddp->ddp_lsat.sat_port;
77
78 /*
79 * The checksum calculation is done after all of the other bytes have
80 * been filled in.
81 */
82 if (ddp_cksum)
83 deh->deh_sum = at_cksum(m, sizeof(int));
84 else
85 deh->deh_sum = 0;
86 deh->deh_bytes = htonl(deh->deh_bytes);
87
88 #ifdef NETATALK_DEBUG
89 printf ("ddp_output: from %d.%d:%d to %d.%d:%d\n",
90 ntohs(deh->deh_snet), deh->deh_snode, deh->deh_sport,
91 ntohs(deh->deh_dnet), deh->deh_dnode, deh->deh_dport);
92 #endif
93 return (ddp_route(m, &ddp->ddp_route));
94 }
95
96 u_short
97 at_cksum(struct mbuf *m, int skip)
98 {
99 u_char *data, *end;
100 u_long cksum = 0;
101
102 for (; m; m = m->m_next) {
103 for (data = mtod(m, u_char *), end = data + m->m_len;
104 data < end; data++) {
105 if (skip) {
106 skip--;
107 continue;
108 }
109 cksum = (cksum + *data) << 1;
110 if (cksum & 0x00010000)
111 cksum++;
112 cksum &= 0x0000ffff;
113 }
114 }
115
116 if (cksum == 0)
117 cksum = 0x0000ffff;
118 return ((u_short)cksum);
119 }
120
121 int
122 ddp_route(struct mbuf *m, struct route *ro)
123 {
124 struct sockaddr_at gate;
125 struct elaphdr *elh;
126 struct mbuf *m0;
127 struct at_ifaddr *aa = NULL;
128 struct ifnet *ifp = NULL;
129 u_short net;
130
131 #if 0
132 /* Check for net zero, node zero ("myself") */
133 if (satosat(&ro->ro_dst)->sat_addr.s_net == ATADDR_ANYNET
134 && satosat(&ro->ro_dst)->sat_addr.s_node == ATADDR_ANYNODE) {
135 /* Find the loopback interface */
136 }
137 #endif
138
139 /*
140 * If we have a route, find the ifa that refers to this route. I.e
141 * the ifa used to get to the gateway.
142 */
143 if ((ro->ro_rt == NULL) || (ro->ro_rt->rt_ifa == NULL) ||
144 ((ifp = ro->ro_rt->rt_ifa->ifa_ifp) == NULL))
145 rtalloc(ro);
146 if ((ro->ro_rt != NULL) && (ro->ro_rt->rt_ifa) &&
147 (ifp = ro->ro_rt->rt_ifa->ifa_ifp)) {
148 net = ntohs(satosat(ro->ro_rt->rt_gateway)->sat_addr.s_net);
149 for (aa = at_ifaddr_list; aa != NULL; aa = aa->aa_next) {
150 if (((net == 0) || (aa->aa_ifp == ifp)) &&
151 net >= ntohs(aa->aa_firstnet) &&
152 net <= ntohs(aa->aa_lastnet))
153 break;
154 }
155 } else {
156 m_freem(m);
157 #ifdef NETATALK_DEBUG
158 if (ro->ro_rt == NULL)
159 printf ("ddp_route: no ro_rt.\n");
160 else if (ro->ro_rt->rt_ifa == NULL)
161 printf ("ddp_route: no ro_rt->rt_ifa\n");
162 else
163 printf ("ddp_route: no ro_rt->rt_ifa->ifa_ifp\n");
164 #endif
165 return (ENETUNREACH);
166 }
167
168 if (aa == NULL) {
169 #ifdef NETATALK_DEBUG
170 printf("ddp_route: no atalk address found for %s\n",
171 ifp->if_xname);
172 #endif
173 m_freem(m);
174 return (ENETUNREACH);
175 }
176
177 /*
178 * If the destination address is on a directly attached node use
179 * that, else use the official gateway.
180 */
181 if (ntohs(satosat(&ro->ro_dst)->sat_addr.s_net) >=
182 ntohs(aa->aa_firstnet) &&
183 ntohs(satosat(&ro->ro_dst)->sat_addr.s_net) <=
184 ntohs(aa->aa_lastnet))
185 gate = *satosat(&ro->ro_dst);
186 else
187 gate = *satosat(ro->ro_rt->rt_gateway);
188
189 /*
190 * There are several places in the kernel where data is added to an
191 * mbuf without ensuring that the mbuf pointer is aligned. This is
192 * bad for transition routing, since phase 1 and phase 2 packets end
193 * up poorly aligned due to the three byte elap header.
194 *
195 * XXXRW: kern/4184 suggests that an m_pullup() of (m) should take
196 * place here to address possible alignment issues.
197 *
198 * XXXRW: This appears not to handle M_PKTHDR properly, as it doesn't
199 * move the existing header from the old packet to the new one.
200 * Posibly should call M_MOVE_PKTHDR()? This would also allow
201 * removing mac_mbuf_copy().
202 */
203 if (!(aa->aa_flags & AFA_PHASE2)) {
204 MGET(m0, M_DONTWAIT, MT_DATA);
205 if (m0 == NULL) {
206 m_freem(m);
207 printf("ddp_route: no buffers\n");
208 return (ENOBUFS);
209 }
210 #ifdef MAC
211 mac_mbuf_copy(m, m0);
212 #endif
213 m0->m_next = m;
214 /* XXX perhaps we ought to align the header? */
215 m0->m_len = SZ_ELAPHDR;
216 m = m0;
217
218 elh = mtod(m, struct elaphdr *);
219 elh->el_snode = satosat(&aa->aa_addr)->sat_addr.s_node;
220 elh->el_type = ELAP_DDPEXTEND;
221 elh->el_dnode = gate.sat_addr.s_node;
222 }
223 ro->ro_rt->rt_use++;
224
225 #ifdef NETATALK_DEBUG
226 printf ("ddp_route: from %d.%d to %d.%d, via %d.%d (%s)\n",
227 ntohs(satosat(&aa->aa_addr)->sat_addr.s_net),
228 satosat(&aa->aa_addr)->sat_addr.s_node,
229 ntohs(satosat(&ro->ro_dst)->sat_addr.s_net),
230 satosat(&ro->ro_dst)->sat_addr.s_node,
231 ntohs(gate.sat_addr.s_net), gate.sat_addr.s_node, ifp->if_xname);
232 #endif
233
234 /* Short-circuit the output if we're sending this to ourself. */
235 if ((satosat(&aa->aa_addr)->sat_addr.s_net ==
236 satosat(&ro->ro_dst)->sat_addr.s_net) &&
237 (satosat(&aa->aa_addr)->sat_addr.s_node ==
238 satosat(&ro->ro_dst)->sat_addr.s_node))
239 return (if_simloop(ifp, m, gate.sat_family, 0));
240
241 /* XXX */
242 return ((*ifp->if_output)(ifp, m, (struct sockaddr *)&gate, NULL));
243 }
244
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