1 /* $NetBSD: ddp_output.c,v 1.19 2016/06/20 06:46:38 knakahara 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 1.19 2016/06/20 06:46:38 knakahara Exp $");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/mbuf.h>
35 #include <sys/socket.h>
36 #include <sys/errno.h>
37 #include <sys/syslog.h>
38
39 #include <net/if.h>
40 #include <net/route.h>
41 #include <net/if_ether.h>
42
43 #include <netinet/in.h>
44 #undef s_net
45
46 #include <netatalk/at.h>
47 #include <netatalk/at_var.h>
48 #include <netatalk/ddp.h>
49 #include <netatalk/ddp_var.h>
50 #include <netatalk/at_extern.h>
51
52 int ddp_cksum = 1;
53
54 int
ddp_output(struct mbuf * m,struct ddpcb * ddp)55 ddp_output(struct mbuf *m, struct ddpcb *ddp)
56 {
57 struct ddpehdr *deh;
58
59 M_PREPEND(m, sizeof(struct ddpehdr), M_DONTWAIT);
60 if (!m)
61 return (ENOBUFS);
62
63 deh = mtod(m, struct ddpehdr *);
64 deh->deh_pad = 0;
65 deh->deh_hops = 0;
66
67 deh->deh_len = m->m_pkthdr.len;
68
69 deh->deh_dnet = ddp->ddp_fsat.sat_addr.s_net;
70 deh->deh_dnode = ddp->ddp_fsat.sat_addr.s_node;
71 deh->deh_dport = ddp->ddp_fsat.sat_port;
72 deh->deh_snet = ddp->ddp_lsat.sat_addr.s_net;
73 deh->deh_snode = ddp->ddp_lsat.sat_addr.s_node;
74 deh->deh_sport = ddp->ddp_lsat.sat_port;
75
76 /*
77 * The checksum calculation is done after all of the other bytes have
78 * been filled in.
79 */
80 if (ddp_cksum)
81 deh->deh_sum = at_cksum(m, sizeof(int));
82 else
83 deh->deh_sum = 0;
84 deh->deh_bytes = htonl(deh->deh_bytes);
85
86 return ddp_route(m, &ddp->ddp_route);
87 }
88
89 u_short
at_cksum(struct mbuf * m,int skip)90 at_cksum(struct mbuf *m, int skip)
91 {
92 u_char *data, *end;
93 u_long cksum = 0;
94
95 for (; m; m = m->m_next) {
96 for (data = mtod(m, u_char *), end = data + m->m_len;
97 data < end; data++) {
98 if (skip) {
99 skip--;
100 continue;
101 }
102 cksum = (cksum + *data) << 1;
103 if (cksum & 0x00010000)
104 cksum++;
105 cksum &= 0x0000ffff;
106 }
107 }
108
109 if (cksum == 0) {
110 cksum = 0x0000ffff;
111 }
112 return (u_short)cksum;
113 }
114
115 int
ddp_route(struct mbuf * m,struct route * ro)116 ddp_route(struct mbuf *m, struct route *ro)
117 {
118 struct rtentry *rt;
119 struct sockaddr_at gate;
120 struct elaphdr *elh;
121 struct at_ifaddr *aa = NULL;
122 struct ifnet *ifp = NULL;
123 uint16_t net;
124 uint8_t loopback = 0;
125
126 if ((rt = rtcache_validate(ro)) != NULL && (ifp = rt->rt_ifp) != NULL) {
127 const struct sockaddr_at *dst = satocsat(rtcache_getdst(ro));
128 uint16_t dnet = dst->sat_addr.s_net;
129 uint8_t dnode = dst->sat_addr.s_node;
130 net = satosat(rt->rt_gateway)->sat_addr.s_net;
131
132 TAILQ_FOREACH(aa, &at_ifaddr, aa_list) {
133 if (ntohs(net) >= ntohs(aa->aa_firstnet) &&
134 ntohs(net) <= ntohs(aa->aa_lastnet)) {
135 /* Are we talking to ourselves? */
136 if (dnet == aa->aa_addr.sat_addr.s_net &&
137 dnode == aa->aa_addr.sat_addr.s_node) {
138 /* If to us, redirect to lo0. */
139 ifp = lo0ifp;
140 }
141 /* Or is it a broadcast? */
142 else if (dnet == aa->aa_addr.sat_addr.s_net &&
143 dnode == 255) {
144 /* If broadcast, loop back a copy. */
145 loopback = 1;
146 }
147 break;
148 }
149 }
150 }
151 if (aa == NULL) {
152 #ifdef NETATALKDEBUG
153 printf("%s: no address found\n", __func__);
154 #endif
155 m_freem(m);
156 return EINVAL;
157 }
158 /*
159 * There are several places in the kernel where data is added to
160 * an mbuf without ensuring that the mbuf pointer is aligned.
161 * This is bad for transition routing, since phase 1 and phase 2
162 * packets end up poorly aligned due to the three byte elap header.
163 */
164 if (!(aa->aa_flags & AFA_PHASE2)) {
165 M_PREPEND(m, SZ_ELAPHDR, M_DONTWAIT);
166 if (m == NULL)
167 return ENOBUFS;
168
169 elh = mtod(m, struct elaphdr *);
170 elh->el_snode = satosat(&aa->aa_addr)->sat_addr.s_node;
171 elh->el_type = ELAP_DDPEXTEND;
172 if (ntohs(satocsat(rtcache_getdst(ro))->sat_addr.s_net) >=
173 ntohs(aa->aa_firstnet) &&
174 ntohs(satocsat(rtcache_getdst(ro))->sat_addr.s_net) <=
175 ntohs(aa->aa_lastnet)) {
176 elh->el_dnode =
177 satocsat(rtcache_getdst(ro))->sat_addr.s_node;
178 } else {
179 elh->el_dnode =
180 satosat(rt->rt_gateway)->sat_addr.s_node;
181 }
182 }
183 if (ntohs(satocsat(rtcache_getdst(ro))->sat_addr.s_net) >=
184 ntohs(aa->aa_firstnet) &&
185 ntohs(satocsat(rtcache_getdst(ro))->sat_addr.s_net) <=
186 ntohs(aa->aa_lastnet)) {
187 gate = *satocsat(rtcache_getdst(ro));
188 } else {
189 gate = *satosat(rt->rt_gateway);
190 }
191 rt->rt_use++;
192
193 #if IFA_STATS
194 aa->aa_ifa.ifa_data.ifad_outbytes += m->m_pkthdr.len;
195 #endif
196
197 /* XXX */
198 if (loopback && rtcache_getdst(ro)->sa_family == AF_APPLETALK) {
199 struct mbuf *copym = m_copypacket(m, M_DONTWAIT);
200
201 #ifdef NETATALKDEBUG
202 printf("Looping back (not AARP).\n");
203 #endif
204 looutput(lo0ifp, copym, rtcache_getdst(ro), NULL);
205 }
206 return if_output_lock(ifp, ifp, m, (struct sockaddr *)&gate, NULL);
207 }
208