1 /* $NetBSD: ddp_output.c,v 1.22 2023/03/30 17:48:10 riastradh Exp $ */
2
3 /*
4 * Copyright (c) 1990,1991 Regents of The University of Michigan.
5 * All Rights Reserved.
6 *
7 * Permission to use, copy, modify, and distribute this software and
8 * its documentation for any purpose and without fee is hereby granted,
9 * provided that the above copyright notice appears in all copies and
10 * that both that copyright notice and this permission notice appear
11 * in supporting documentation, and that the name of The University
12 * of Michigan not be used in advertising or publicity pertaining to
13 * distribution of the software without specific, written prior
14 * permission. This software is supplied as is without expressed or
15 * implied warranties of any kind.
16 *
17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
19 *
20 * Research Systems Unix Group
21 * The University of Michigan
22 * c/o Wesley Craig
23 * 535 W. William Street
24 * Ann Arbor, Michigan
25 * +1-313-764-2278
26 * netatalk@umich.edu
27 */
28
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: ddp_output.c,v 1.22 2023/03/30 17:48:10 riastradh Exp $");
31 #include "opt_atalk.h"
32
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/mbuf.h>
36 #include <sys/socket.h>
37 #include <sys/errno.h>
38 #include <sys/syslog.h>
39
40 #include <net/if.h>
41 #include <net/route.h>
42 #include <net/if_ether.h>
43
44 #include <netinet/in.h>
45 #undef s_net
46
47 #include <netatalk/at.h>
48 #include <netatalk/at_var.h>
49 #include <netatalk/ddp.h>
50 #include <netatalk/ddp_var.h>
51 #include <netatalk/at_extern.h>
52
53 int ddp_cksum = 1;
54
55 int
ddp_output(struct mbuf * m,struct ddpcb * ddp)56 ddp_output(struct mbuf *m, struct ddpcb *ddp)
57 {
58 struct ddpehdr *deh;
59
60 M_PREPEND(m, sizeof(struct ddpehdr), M_DONTWAIT);
61 if (!m)
62 return (ENOBUFS);
63
64 deh = mtod(m, struct ddpehdr *);
65 deh->deh_pad = 0;
66 deh->deh_hops = 0;
67
68 deh->deh_len = m->m_pkthdr.len;
69
70 deh->deh_dnet = ddp->ddp_fsat.sat_addr.s_net;
71 deh->deh_dnode = ddp->ddp_fsat.sat_addr.s_node;
72 deh->deh_dport = ddp->ddp_fsat.sat_port;
73 deh->deh_snet = ddp->ddp_lsat.sat_addr.s_net;
74 deh->deh_snode = ddp->ddp_lsat.sat_addr.s_node;
75 deh->deh_sport = ddp->ddp_lsat.sat_port;
76
77 /*
78 * The checksum calculation is done after all of the other bytes have
79 * been filled in.
80 */
81 if (ddp_cksum)
82 deh->deh_sum = at_cksum(m, sizeof(int));
83 else
84 deh->deh_sum = 0;
85 deh->deh_bytes = htonl(deh->deh_bytes);
86
87 return ddp_route(m, &ddp->ddp_route);
88 }
89
90 u_short
at_cksum(struct mbuf * m,int skip)91 at_cksum(struct mbuf *m, int skip)
92 {
93 u_char *data, *end;
94 u_long cksum = 0;
95
96 for (; m; m = m->m_next) {
97 for (data = mtod(m, u_char *), end = data + m->m_len;
98 data < end; data++) {
99 if (skip) {
100 skip--;
101 continue;
102 }
103 cksum = (cksum + *data) << 1;
104 if (cksum & 0x00010000)
105 cksum++;
106 cksum &= 0x0000ffff;
107 }
108 }
109
110 if (cksum == 0) {
111 cksum = 0x0000ffff;
112 }
113 return (u_short)cksum;
114 }
115
116 int
ddp_route(struct mbuf * m,struct route * ro)117 ddp_route(struct mbuf *m, struct route *ro)
118 {
119 struct rtentry *rt;
120 struct sockaddr_at gate;
121 struct elaphdr *elh;
122 struct at_ifaddr *aa = NULL;
123 struct ifnet *ifp = NULL;
124 uint16_t net;
125 uint8_t loopback = 0;
126 int error;
127
128 if ((rt = rtcache_validate(ro)) != NULL && (ifp = rt->rt_ifp) != NULL) {
129 const struct sockaddr_at *dst = satocsat(rtcache_getdst(ro));
130 uint16_t dnet = dst->sat_addr.s_net;
131 uint8_t dnode = dst->sat_addr.s_node;
132 net = satosat(rt->rt_gateway)->sat_addr.s_net;
133
134 TAILQ_FOREACH(aa, &at_ifaddr, aa_list) {
135 if (ntohs(net) >= ntohs(aa->aa_firstnet) &&
136 ntohs(net) <= ntohs(aa->aa_lastnet)) {
137 /* Are we talking to ourselves? */
138 if (dnet == aa->aa_addr.sat_addr.s_net &&
139 dnode == aa->aa_addr.sat_addr.s_node) {
140 /* If to us, redirect to lo0. */
141 ifp = lo0ifp;
142 }
143 /* Or is it a broadcast? */
144 else if (dnet == aa->aa_addr.sat_addr.s_net &&
145 dnode == 255) {
146 /* If broadcast, loop back a copy. */
147 loopback = 1;
148 }
149 break;
150 }
151 }
152 }
153 if (aa == NULL) {
154 #ifdef NETATALKDEBUG
155 printf("%s: no address found\n", __func__);
156 #endif
157 m_freem(m);
158 error = EINVAL;
159 goto out;
160 }
161 /*
162 * There are several places in the kernel where data is added to
163 * an mbuf without ensuring that the mbuf pointer is aligned.
164 * This is bad for transition routing, since phase 1 and phase 2
165 * packets end up poorly aligned due to the three byte elap header.
166 */
167 if (!(aa->aa_flags & AFA_PHASE2)) {
168 M_PREPEND(m, SZ_ELAPHDR, M_DONTWAIT);
169 if (m == NULL) {
170 error = ENOBUFS;
171 goto out;
172 }
173
174 elh = mtod(m, struct elaphdr *);
175 elh->el_snode = aa->aa_addr.sat_addr.s_node;
176 elh->el_type = ELAP_DDPEXTEND;
177 if (ntohs(satocsat(rtcache_getdst(ro))->sat_addr.s_net) >=
178 ntohs(aa->aa_firstnet) &&
179 ntohs(satocsat(rtcache_getdst(ro))->sat_addr.s_net) <=
180 ntohs(aa->aa_lastnet)) {
181 elh->el_dnode =
182 satocsat(rtcache_getdst(ro))->sat_addr.s_node;
183 } else {
184 elh->el_dnode =
185 satosat(rt->rt_gateway)->sat_addr.s_node;
186 }
187 }
188 if (ntohs(satocsat(rtcache_getdst(ro))->sat_addr.s_net) >=
189 ntohs(aa->aa_firstnet) &&
190 ntohs(satocsat(rtcache_getdst(ro))->sat_addr.s_net) <=
191 ntohs(aa->aa_lastnet)) {
192 gate = *satocsat(rtcache_getdst(ro));
193 } else {
194 gate = *satosat(rt->rt_gateway);
195 }
196 rt->rt_use++;
197
198 #if IFA_STATS
199 aa->aa_ifa.ifa_data.ifad_outbytes += m->m_pkthdr.len;
200 #endif
201
202 /* XXX */
203 if (loopback && rtcache_getdst(ro)->sa_family == AF_APPLETALK) {
204 struct mbuf *copym = m_copypacket(m, M_DONTWAIT);
205
206 #ifdef NETATALKDEBUG
207 printf("Looping back (not AARP).\n");
208 #endif
209 looutput(lo0ifp, copym, rtcache_getdst(ro), NULL);
210 }
211
212 error = if_output_lock(ifp, ifp, m, (struct sockaddr *)&gate, NULL);
213 out:
214 rtcache_unref(rt, ro);
215 return error;
216 }
217