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1.1 root 1: /* ip_output.c 6.1 83/07/29 */
2:
3: #include "../h/param.h"
4: #include "../h/mbuf.h"
5: #include "../h/errno.h"
6: #include "../h/socket.h"
7: #include "../h/socketvar.h"
8:
9: #include "../net/if.h"
10: #include "../net/route.h"
11:
12: #include "../netinet/in.h"
13: #include "../netinet/in_systm.h"
14: #include "../netinet/ip.h"
15: #include "../netinet/ip_var.h"
16:
17: #include "../machine/mtpr.h"
18:
19: ip_output(m, opt, ro, flags)
20: struct mbuf *m;
21: struct mbuf *opt;
22: struct route *ro;
23: int flags;
24: {
25: register struct ip *ip = mtod(m, struct ip *);
26: register struct ifnet *ifp;
27: int len, hlen = sizeof (struct ip), off, error = 0;
28: struct route iproute;
29: struct sockaddr *dst;
30:
31: if (opt) /* XXX */
32: (void) m_free(opt); /* XXX */
33: /*
34: * Fill in IP header.
35: */
36: ip->ip_hl = hlen >> 2;
37: if ((flags & IP_FORWARDING) == 0) {
38: ip->ip_v = IPVERSION;
39: ip->ip_off &= IP_DF;
40: ip->ip_id = htons(ip_id++);
41: }
42:
43: /*
44: * Route packet.
45: */
46: if (ro == 0) {
47: ro = &iproute;
48: bzero((caddr_t)ro, sizeof (*ro));
49: }
50: dst = &ro->ro_dst;
51: if (ro->ro_rt == 0) {
52: ro->ro_dst.sa_family = AF_INET;
53: ((struct sockaddr_in *)&ro->ro_dst)->sin_addr = ip->ip_dst;
54: /*
55: * If routing to interface only,
56: * short circuit routing lookup.
57: */
58: if (flags & IP_ROUTETOIF) {
59: ifp = if_ifonnetof(in_netof(ip->ip_dst));
60: if (ifp == 0) {
61: error = ENETUNREACH;
62: goto bad;
63: }
64: goto gotif;
65: }
66: rtalloc(ro);
67: }
68: if (ro->ro_rt == 0 || (ifp = ro->ro_rt->rt_ifp) == 0) {
69: error = ENETUNREACH;
70: goto bad;
71: }
72: ro->ro_rt->rt_use++;
73: if (ro->ro_rt->rt_flags & RTF_GATEWAY)
74: dst = &ro->ro_rt->rt_gateway;
75: gotif:
76: #ifndef notdef
77: /*
78: * If source address not specified yet, use address
79: * of outgoing interface.
80: */
81: if (in_lnaof(ip->ip_src) == INADDR_ANY)
82: ip->ip_src.s_addr =
83: ((struct sockaddr_in *)&ifp->if_addr)->sin_addr.s_addr;
84: #endif
85:
86: /*
87: * Look for broadcast address and
88: * and verify user is allowed to send
89: * such a packet.
90: */
91: if (in_lnaof(((struct sockaddr_in *)dst)->sin_addr) == INADDR_ANY) {
92: if ((ifp->if_flags & IFF_BROADCAST) == 0) {
93: error = EADDRNOTAVAIL;
94: goto bad;
95: }
96: if ((flags & IP_ALLOWBROADCAST) == 0) {
97: error = EACCES;
98: goto bad;
99: }
100: /* don't allow broadcast messages to be fragmented */
101: if (ip->ip_len > ifp->if_mtu) {
102: error = EMSGSIZE;
103: goto bad;
104: }
105: }
106:
107: /*
108: * If small enough for interface, can just send directly.
109: */
110: if (ip->ip_len <= ifp->if_mtu) {
111: ip->ip_len = htons((u_short)ip->ip_len);
112: ip->ip_off = htons((u_short)ip->ip_off);
113: ip->ip_sum = 0;
114: ip->ip_sum = in_cksum(m, hlen);
115: error = (*ifp->if_output)(ifp, m, dst);
116: goto done;
117: }
118:
119: /*
120: * Too large for interface; fragment if possible.
121: * Must be able to put at least 8 bytes per fragment.
122: */
123: if (ip->ip_off & IP_DF) {
124: error = EMSGSIZE;
125: goto bad;
126: }
127: len = (ifp->if_mtu - hlen) &~ 7;
128: if (len < 8) {
129: error = EMSGSIZE;
130: goto bad;
131: }
132:
133: /*
134: * Discard IP header from logical mbuf for m_copy's sake.
135: * Loop through length of segment, make a copy of each
136: * part and output.
137: */
138: m->m_len -= sizeof (struct ip);
139: m->m_off += sizeof (struct ip);
140: for (off = 0; off < ip->ip_len-hlen; off += len) {
141: struct mbuf *mh = m_get(M_DONTWAIT, MT_HEADER);
142: struct ip *mhip;
143:
144: MBUFNULL(9, mh); /* for debugging */
145: if (mh == 0) {
146: error = ENOBUFS;
147: goto bad;
148: }
149: mh->m_off = MMAXOFF - hlen;
150: mhip = mtod(mh, struct ip *);
151: *mhip = *ip;
152: if (hlen > sizeof (struct ip)) {
153: int olen = ip_optcopy(ip, mhip, off);
154: mh->m_len = sizeof (struct ip) + olen;
155: } else
156: mh->m_len = sizeof (struct ip);
157: mhip->ip_off = off >> 3;
1.1.1.2 ! root 158: if (off + len >= ip->ip_len-hlen) {
1.1 root 159: len = mhip->ip_len = ip->ip_len - hlen - off;
1.1.1.2 ! root 160: /*
! 161: * if the output packet has M flag set, make sure
! 162: * this flag is set for the last fragment
! 163: */
! 164: if (ip->ip_off & IP_MF)
! 165: mhip->ip_off |= IP_MF;
! 166: } else {
1.1 root 167: mhip->ip_len = len;
168: mhip->ip_off |= IP_MF;
169: }
170: mhip->ip_len += sizeof (struct ip);
171: mhip->ip_len = htons((u_short)mhip->ip_len);
172: mh->m_next = m_copy(m, off, len);
173: MBUFNULL(36, mh->m_next); /* for debugging */
174: if (mh->m_next == 0) {
175: (void) m_free(mh);
176: error = ENOBUFS; /* ??? */
177: goto bad;
178: }
179: mhip->ip_off = htons((u_short)mhip->ip_off);
180: mhip->ip_sum = 0;
181: mhip->ip_sum = in_cksum(mh, hlen);
182: if (error = (*ifp->if_output)(ifp, mh, dst))
183: break;
184: }
185: m_freem(m);
186: goto done;
187:
188: bad:
189: m_freem(m);
190: done:
191: if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt)
192: RTFREE(ro->ro_rt);
193: return (error);
194: }
195:
196: /*
197: * Copy options from ip to jp.
198: * If off is 0 all options are copied
199: * otherwise copy selectively.
200: */
201: ip_optcopy(ip, jp, off)
202: struct ip *ip, *jp;
203: int off;
204: {
205: register u_char *cp, *dp;
206: int opt, optlen, cnt;
207:
208: cp = (u_char *)(ip + 1);
209: dp = (u_char *)(jp + 1);
210: cnt = (ip->ip_hl << 2) - sizeof (struct ip);
211: for (; cnt > 0; cnt -= optlen, cp += optlen) {
212: opt = cp[0];
213: if (opt == IPOPT_EOL)
214: break;
215: if (opt == IPOPT_NOP)
216: optlen = 1;
217: else
218: optlen = cp[1];
219: if (optlen > cnt) /* XXX */
220: optlen = cnt; /* XXX */
221: if (off == 0 || IPOPT_COPIED(opt)) {
222: bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen);
223: dp += optlen;
224: }
225: }
226: for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
227: *dp++ = IPOPT_EOL;
228: return (optlen);
229: }
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