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1.1 root 1: /*
2: * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
3: * All rights reserved.
4: *
5: * Redistribution and use in source and binary forms are permitted
6: * provided that the above copyright notice and this paragraph are
7: * duplicated in all such forms and that any documentation,
8: * advertising materials, and other materials related to such
9: * distribution and use acknowledge that the software was developed
10: * by the University of California, Berkeley. The name of the
11: * University may not be used to endorse or promote products derived
12: * from this software without specific prior written permission.
13: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14: * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15: * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16: *
17: * @(#)ip_output.c 7.13 (Berkeley) 6/29/88
18: */
19:
20: #include "param.h"
21: #include "mbuf.h"
22: #include "errno.h"
23: #include "protosw.h"
24: #include "socket.h"
25: #include "socketvar.h"
26:
27: #include "../net/if.h"
28: #include "../net/route.h"
29:
30: #include "in.h"
31: #include "in_pcb.h"
32: #include "in_systm.h"
33: #include "in_var.h"
34: #include "ip.h"
35: #include "ip_var.h"
36:
37: #ifdef vax
38: #include "../machine/mtpr.h"
39: #endif
40:
41: struct mbuf *ip_insertoptions();
42:
43: /*
44: * IP output. The packet in mbuf chain m contains a skeletal IP
45: * header (with len, off, ttl, proto, tos, src, dst).
46: * The mbuf chain containing the packet will be freed.
47: * The mbuf opt, if present, will not be freed.
48: */
49: ip_output(m0, opt, ro, flags)
50: struct mbuf *m0;
51: struct mbuf *opt;
52: struct route *ro;
53: int flags;
54: {
55: register struct ip *ip, *mhip;
56: register struct ifnet *ifp;
57: register struct mbuf *m = m0;
58: register int hlen = sizeof (struct ip);
59: int len, off, error = 0;
60: struct route iproute;
61: struct sockaddr_in *dst;
62:
63: if (opt) {
64: m = ip_insertoptions(m, opt, &len);
65: hlen = len;
66: }
67: ip = mtod(m, struct ip *);
68: /*
69: * Fill in IP header.
70: */
71: if ((flags & IP_FORWARDING) == 0) {
72: ip->ip_v = IPVERSION;
73: ip->ip_off &= IP_DF;
74: ip->ip_id = htons(ip_id++);
75: ip->ip_hl = hlen >> 2;
76: } else
77: hlen = ip->ip_hl << 2;
78:
79: /*
80: * Route packet.
81: */
82: if (ro == 0) {
83: ro = &iproute;
84: bzero((caddr_t)ro, sizeof (*ro));
85: }
86: dst = (struct sockaddr_in *)&ro->ro_dst;
87: /*
88: * If there is a cached route,
89: * check that it is to the same destination
90: * and is still up. If not, free it and try again.
91: */
92: if (ro->ro_rt && ((ro->ro_rt->rt_flags & RTF_UP) == 0 ||
93: dst->sin_addr.s_addr != ip->ip_dst.s_addr)) {
94: RTFREE(ro->ro_rt);
95: ro->ro_rt = (struct rtentry *)0;
96: }
97: if (ro->ro_rt == 0) {
98: dst->sin_family = AF_INET;
99: dst->sin_addr = ip->ip_dst;
100: }
101: /*
102: * If routing to interface only,
103: * short circuit routing lookup.
104: */
105: if (flags & IP_ROUTETOIF) {
106: struct in_ifaddr *ia;
107:
108: ia = (struct in_ifaddr *)ifa_ifwithdstaddr((struct sockaddr *)dst);
109: if (ia == 0)
110: ia = in_iaonnetof(in_netof(ip->ip_dst));
111: if (ia == 0) {
112: error = ENETUNREACH;
113: goto bad;
114: }
115: ifp = ia->ia_ifp;
116: } else {
117: if (ro->ro_rt == 0)
118: rtalloc(ro);
119: if (ro->ro_rt == 0 || (ifp = ro->ro_rt->rt_ifp) == 0) {
120: if (in_localaddr(ip->ip_dst))
121: error = EHOSTUNREACH;
122: else
123: error = ENETUNREACH;
124: goto bad;
125: }
126: ro->ro_rt->rt_use++;
127: if (ro->ro_rt->rt_flags & RTF_GATEWAY)
128: dst = (struct sockaddr_in *)&ro->ro_rt->rt_gateway;
129: }
130: #ifndef notdef
131: /*
132: * If source address not specified yet, use address
133: * of outgoing interface.
134: */
135: if (ip->ip_src.s_addr == INADDR_ANY) {
136: register struct in_ifaddr *ia;
137:
138: for (ia = in_ifaddr; ia; ia = ia->ia_next)
139: if (ia->ia_ifp == ifp) {
140: ip->ip_src = IA_SIN(ia)->sin_addr;
141: break;
142: }
143: }
144: #endif
145: /*
146: * Look for broadcast address and
147: * and verify user is allowed to send
148: * such a packet.
149: */
150: if (in_broadcast(dst->sin_addr)) {
151: if ((ifp->if_flags & IFF_BROADCAST) == 0) {
152: error = EADDRNOTAVAIL;
153: goto bad;
154: }
155: if ((flags & IP_ALLOWBROADCAST) == 0) {
156: error = EACCES;
157: goto bad;
158: }
159: /* don't allow broadcast messages to be fragmented */
160: if (ip->ip_len > ifp->if_mtu) {
161: error = EMSGSIZE;
162: goto bad;
163: }
164: }
165:
166: /*
167: * If small enough for interface, can just send directly.
168: */
169: if (ip->ip_len <= ifp->if_mtu) {
170: ip->ip_len = htons((u_short)ip->ip_len);
171: ip->ip_off = htons((u_short)ip->ip_off);
172: ip->ip_sum = 0;
173: ip->ip_sum = in_cksum(m, hlen);
174: error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst);
175: goto done;
176: }
177:
178: /*
179: * Too large for interface; fragment if possible.
180: * Must be able to put at least 8 bytes per fragment.
181: */
182: if (ip->ip_off & IP_DF) {
183: error = EMSGSIZE;
184: goto bad;
185: }
186: len = (ifp->if_mtu - hlen) &~ 7;
187: if (len < 8) {
188: error = EMSGSIZE;
189: goto bad;
190: }
191:
192: {
193: int mhlen, firstlen = len;
194: struct mbuf **mnext = &m->m_act;
195:
196: /*
197: * Loop through length of segment after first fragment,
198: * make new header and copy data of each part and link onto chain.
199: */
200: m0 = m;
201: mhlen = sizeof (struct ip);
202: for (off = hlen + len; off < ip->ip_len; off += len) {
203: MGET(m, M_DONTWAIT, MT_HEADER);
204: if (m == 0) {
205: error = ENOBUFS;
206: goto sendorfree;
207: }
208: m->m_off = MMAXOFF - hlen;
209: mhip = mtod(m, struct ip *);
210: *mhip = *ip;
211: if (hlen > sizeof (struct ip)) {
212: mhlen = ip_optcopy(ip, mhip) + sizeof (struct ip);
213: mhip->ip_hl = mhlen >> 2;
214: }
215: m->m_len = mhlen;
216: mhip->ip_off = ((off - hlen) >> 3) + (ip->ip_off & ~IP_MF);
217: if (ip->ip_off & IP_MF)
218: mhip->ip_off |= IP_MF;
219: if (off + len >= ip->ip_len)
220: len = ip->ip_len - off;
221: else
222: mhip->ip_off |= IP_MF;
223: mhip->ip_len = htons((u_short)(len + mhlen));
224: m->m_next = m_copy(m0, off, len);
225: if (m->m_next == 0) {
226: error = ENOBUFS; /* ??? */
227: goto sendorfree;
228: }
229: mhip->ip_off = htons((u_short)mhip->ip_off);
230: mhip->ip_sum = 0;
231: mhip->ip_sum = in_cksum(m, mhlen);
232: *mnext = m;
233: mnext = &m->m_act;
234: }
235: /*
236: * Update first fragment by trimming what's been copied out
237: * and updating header, then send each fragment (in order).
238: */
239: m_adj(m0, hlen + firstlen - ip->ip_len);
240: ip->ip_len = htons((u_short)(hlen + firstlen));
241: ip->ip_off = htons((u_short)(ip->ip_off | IP_MF));
242: ip->ip_sum = 0;
243: ip->ip_sum = in_cksum(m0, hlen);
244: sendorfree:
245: for (m = m0; m; m = m0) {
246: m0 = m->m_act;
247: m->m_act = 0;
248: if (error == 0)
249: error = (*ifp->if_output)(ifp, m,
250: (struct sockaddr *)dst);
251: else
252: m_freem(m);
253: }
254: }
255: done:
256: if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt)
257: RTFREE(ro->ro_rt);
258: return (error);
259: bad:
260: m_freem(m0);
261: goto done;
262: }
263:
264: /*
265: * Insert IP options into preformed packet.
266: * Adjust IP destination as required for IP source routing,
267: * as indicated by a non-zero in_addr at the start of the options.
268: */
269: struct mbuf *
270: ip_insertoptions(m, opt, phlen)
271: register struct mbuf *m;
272: struct mbuf *opt;
273: int *phlen;
274: {
275: register struct ipoption *p = mtod(opt, struct ipoption *);
276: struct mbuf *n;
277: register struct ip *ip = mtod(m, struct ip *);
278: unsigned optlen;
279:
280: optlen = opt->m_len - sizeof(p->ipopt_dst);
281: if (p->ipopt_dst.s_addr)
282: ip->ip_dst = p->ipopt_dst;
283: if (m->m_off >= MMAXOFF || MMINOFF + optlen > m->m_off) {
284: MGET(n, M_DONTWAIT, MT_HEADER);
285: if (n == 0)
286: return (m);
287: m->m_len -= sizeof(struct ip);
288: m->m_off += sizeof(struct ip);
289: n->m_next = m;
290: m = n;
291: m->m_off = MMAXOFF - sizeof(struct ip) - optlen;
292: m->m_len = optlen + sizeof(struct ip);
293: bcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
294: } else {
295: m->m_off -= optlen;
296: m->m_len += optlen;
297: ovbcopy((caddr_t)ip, mtod(m, caddr_t), sizeof(struct ip));
298: }
299: ip = mtod(m, struct ip *);
300: bcopy((caddr_t)p->ipopt_list, (caddr_t)(ip + 1), (unsigned)optlen);
301: *phlen = sizeof(struct ip) + optlen;
302: ip->ip_len += optlen;
303: return (m);
304: }
305:
306: /*
307: * Copy options from ip to jp,
308: * omitting those not copied during fragmentation.
309: */
310: ip_optcopy(ip, jp)
311: struct ip *ip, *jp;
312: {
313: register u_char *cp, *dp;
314: int opt, optlen, cnt;
315:
316: cp = (u_char *)(ip + 1);
317: dp = (u_char *)(jp + 1);
318: cnt = (ip->ip_hl << 2) - sizeof (struct ip);
319: for (; cnt > 0; cnt -= optlen, cp += optlen) {
320: opt = cp[0];
321: if (opt == IPOPT_EOL)
322: break;
323: if (opt == IPOPT_NOP)
324: optlen = 1;
325: else
326: optlen = cp[IPOPT_OLEN];
327: /* bogus lengths should have been caught by ip_dooptions */
328: if (optlen > cnt)
329: optlen = cnt;
330: if (IPOPT_COPIED(opt)) {
331: bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen);
332: dp += optlen;
333: }
334: }
335: for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
336: *dp++ = IPOPT_EOL;
337: return (optlen);
338: }
339:
340: /*
341: * IP socket option processing.
342: */
343: ip_ctloutput(op, so, level, optname, m)
344: int op;
345: struct socket *so;
346: int level, optname;
347: struct mbuf **m;
348: {
349: int error = 0;
350: struct inpcb *inp = sotoinpcb(so);
351:
352: if (level != IPPROTO_IP)
353: error = EINVAL;
354: else switch (op) {
355:
356: case PRCO_SETOPT:
357: switch (optname) {
358: case IP_OPTIONS:
359: return (ip_pcbopts(&inp->inp_options, *m));
360:
361: default:
362: error = EINVAL;
363: break;
364: }
365: break;
366:
367: case PRCO_GETOPT:
368: switch (optname) {
369: case IP_OPTIONS:
370: *m = m_get(M_WAIT, MT_SOOPTS);
371: if (inp->inp_options) {
372: (*m)->m_off = inp->inp_options->m_off;
373: (*m)->m_len = inp->inp_options->m_len;
374: bcopy(mtod(inp->inp_options, caddr_t),
375: mtod(*m, caddr_t), (unsigned)(*m)->m_len);
376: } else
377: (*m)->m_len = 0;
378: break;
379: default:
380: error = EINVAL;
381: break;
382: }
383: break;
384: }
385: if (op == PRCO_SETOPT && *m)
386: (void)m_free(*m);
387: return (error);
388: }
389:
390: /*
391: * Set up IP options in pcb for insertion in output packets.
392: * Store in mbuf with pointer in pcbopt, adding pseudo-option
393: * with destination address if source routed.
394: */
395: ip_pcbopts(pcbopt, m)
396: struct mbuf **pcbopt;
397: register struct mbuf *m;
398: {
399: register cnt, optlen;
400: register u_char *cp;
401: u_char opt;
402:
403: /* turn off any old options */
404: if (*pcbopt)
405: (void)m_free(*pcbopt);
406: *pcbopt = 0;
407: if (m == (struct mbuf *)0 || m->m_len == 0) {
408: /*
409: * Only turning off any previous options.
410: */
411: if (m)
412: (void)m_free(m);
413: return (0);
414: }
415:
416: #ifndef vax
417: if (m->m_len % sizeof(long))
418: goto bad;
419: #endif
420: /*
421: * IP first-hop destination address will be stored before
422: * actual options; move other options back
423: * and clear it when none present.
424: */
425: #if MAX_IPOPTLEN >= MMAXOFF - MMINOFF
426: if (m->m_off + m->m_len + sizeof(struct in_addr) > MAX_IPOPTLEN)
427: goto bad;
428: #else
429: if (m->m_off + m->m_len + sizeof(struct in_addr) > MMAXOFF)
430: goto bad;
431: #endif
432: cnt = m->m_len;
433: m->m_len += sizeof(struct in_addr);
434: cp = mtod(m, u_char *) + sizeof(struct in_addr);
435: ovbcopy(mtod(m, caddr_t), (caddr_t)cp, (unsigned)cnt);
436: bzero(mtod(m, caddr_t), sizeof(struct in_addr));
437:
438: for (; cnt > 0; cnt -= optlen, cp += optlen) {
439: opt = cp[IPOPT_OPTVAL];
440: if (opt == IPOPT_EOL)
441: break;
442: if (opt == IPOPT_NOP)
443: optlen = 1;
444: else {
445: optlen = cp[IPOPT_OLEN];
446: if (optlen <= IPOPT_OLEN || optlen > cnt)
447: goto bad;
448: }
449: switch (opt) {
450:
451: default:
452: break;
453:
454: case IPOPT_LSRR:
455: case IPOPT_SSRR:
456: /*
457: * user process specifies route as:
458: * ->A->B->C->D
459: * D must be our final destination (but we can't
460: * check that since we may not have connected yet).
461: * A is first hop destination, which doesn't appear in
462: * actual IP option, but is stored before the options.
463: */
464: if (optlen < IPOPT_MINOFF - 1 + sizeof(struct in_addr))
465: goto bad;
466: m->m_len -= sizeof(struct in_addr);
467: cnt -= sizeof(struct in_addr);
468: optlen -= sizeof(struct in_addr);
469: cp[IPOPT_OLEN] = optlen;
470: /*
471: * Move first hop before start of options.
472: */
473: bcopy((caddr_t)&cp[IPOPT_OFFSET+1], mtod(m, caddr_t),
474: sizeof(struct in_addr));
475: /*
476: * Then copy rest of options back
477: * to close up the deleted entry.
478: */
479: ovbcopy((caddr_t)(&cp[IPOPT_OFFSET+1] +
480: sizeof(struct in_addr)),
481: (caddr_t)&cp[IPOPT_OFFSET+1],
482: (unsigned)cnt + sizeof(struct in_addr));
483: break;
484: }
485: }
486: *pcbopt = m;
487: return (0);
488:
489: bad:
490: (void)m_free(m);
491: return (EINVAL);
492: }
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