summaryrefslogtreecommitdiffstats
path: root/net/ipv4/ip_options.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/ipv4/ip_options.c')
-rw-r--r--net/ipv4/ip_options.c625
1 files changed, 625 insertions, 0 deletions
diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
new file mode 100644
index 0000000..6d89f3f
--- /dev/null
+++ b/net/ipv4/ip_options.c
@@ -0,0 +1,625 @@
+/*
+ * INET An implementation of the TCP/IP protocol suite for the LINUX
+ * operating system. INET is implemented using the BSD Socket
+ * interface as the means of communication with the user level.
+ *
+ * The options processing module for ip.c
+ *
+ * Version: $Id: ip_options.c,v 1.21 2001/09/01 00:31:50 davem Exp $
+ *
+ * Authors: A.N.Kuznetsov
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <asm/uaccess.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+#include <linux/icmp.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
+#include <net/sock.h>
+#include <net/ip.h>
+#include <net/icmp.h>
+
+/*
+ * Write options to IP header, record destination address to
+ * source route option, address of outgoing interface
+ * (we should already know it, so that this function is allowed be
+ * called only after routing decision) and timestamp,
+ * if we originate this datagram.
+ *
+ * daddr is real destination address, next hop is recorded in IP header.
+ * saddr is address of outgoing interface.
+ */
+
+void ip_options_build(struct sk_buff * skb, struct ip_options * opt,
+ u32 daddr, struct rtable *rt, int is_frag)
+{
+ unsigned char * iph = skb->nh.raw;
+
+ memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options));
+ memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
+ opt = &(IPCB(skb)->opt);
+ opt->is_data = 0;
+
+ if (opt->srr)
+ memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);
+
+ if (!is_frag) {
+ if (opt->rr_needaddr)
+ ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, rt);
+ if (opt->ts_needaddr)
+ ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, rt);
+ if (opt->ts_needtime) {
+ struct timeval tv;
+ __u32 midtime;
+ do_gettimeofday(&tv);
+ midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
+ memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
+ }
+ return;
+ }
+ if (opt->rr) {
+ memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
+ opt->rr = 0;
+ opt->rr_needaddr = 0;
+ }
+ if (opt->ts) {
+ memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
+ opt->ts = 0;
+ opt->ts_needaddr = opt->ts_needtime = 0;
+ }
+}
+
+/*
+ * Provided (sopt, skb) points to received options,
+ * build in dopt compiled option set appropriate for answering.
+ * i.e. invert SRR option, copy anothers,
+ * and grab room in RR/TS options.
+ *
+ * NOTE: dopt cannot point to skb.
+ */
+
+int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)
+{
+ struct ip_options *sopt;
+ unsigned char *sptr, *dptr;
+ int soffset, doffset;
+ int optlen;
+ u32 daddr;
+
+ memset(dopt, 0, sizeof(struct ip_options));
+
+ dopt->is_data = 1;
+
+ sopt = &(IPCB(skb)->opt);
+
+ if (sopt->optlen == 0) {
+ dopt->optlen = 0;
+ return 0;
+ }
+
+ sptr = skb->nh.raw;
+ dptr = dopt->__data;
+
+ if (skb->dst)
+ daddr = ((struct rtable*)skb->dst)->rt_spec_dst;
+ else
+ daddr = skb->nh.iph->daddr;
+
+ if (sopt->rr) {
+ optlen = sptr[sopt->rr+1];
+ soffset = sptr[sopt->rr+2];
+ dopt->rr = dopt->optlen + sizeof(struct iphdr);
+ memcpy(dptr, sptr+sopt->rr, optlen);
+ if (sopt->rr_needaddr && soffset <= optlen) {
+ if (soffset + 3 > optlen)
+ return -EINVAL;
+ dptr[2] = soffset + 4;
+ dopt->rr_needaddr = 1;
+ }
+ dptr += optlen;
+ dopt->optlen += optlen;
+ }
+ if (sopt->ts) {
+ optlen = sptr[sopt->ts+1];
+ soffset = sptr[sopt->ts+2];
+ dopt->ts = dopt->optlen + sizeof(struct iphdr);
+ memcpy(dptr, sptr+sopt->ts, optlen);
+ if (soffset <= optlen) {
+ if (sopt->ts_needaddr) {
+ if (soffset + 3 > optlen)
+ return -EINVAL;
+ dopt->ts_needaddr = 1;
+ soffset += 4;
+ }
+ if (sopt->ts_needtime) {
+ if (soffset + 3 > optlen)
+ return -EINVAL;
+ if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) {
+ dopt->ts_needtime = 1;
+ soffset += 4;
+ } else {
+ dopt->ts_needtime = 0;
+
+ if (soffset + 8 <= optlen) {
+ __u32 addr;
+
+ memcpy(&addr, sptr+soffset-1, 4);
+ if (inet_addr_type(addr) != RTN_LOCAL) {
+ dopt->ts_needtime = 1;
+ soffset += 8;
+ }
+ }
+ }
+ }
+ dptr[2] = soffset;
+ }
+ dptr += optlen;
+ dopt->optlen += optlen;
+ }
+ if (sopt->srr) {
+ unsigned char * start = sptr+sopt->srr;
+ u32 faddr;
+
+ optlen = start[1];
+ soffset = start[2];
+ doffset = 0;
+ if (soffset > optlen)
+ soffset = optlen + 1;
+ soffset -= 4;
+ if (soffset > 3) {
+ memcpy(&faddr, &start[soffset-1], 4);
+ for (soffset-=4, doffset=4; soffset > 3; soffset-=4, doffset+=4)
+ memcpy(&dptr[doffset-1], &start[soffset-1], 4);
+ /*
+ * RFC1812 requires to fix illegal source routes.
+ */
+ if (memcmp(&skb->nh.iph->saddr, &start[soffset+3], 4) == 0)
+ doffset -= 4;
+ }
+ if (doffset > 3) {
+ memcpy(&start[doffset-1], &daddr, 4);
+ dopt->faddr = faddr;
+ dptr[0] = start[0];
+ dptr[1] = doffset+3;
+ dptr[2] = 4;
+ dptr += doffset+3;
+ dopt->srr = dopt->optlen + sizeof(struct iphdr);
+ dopt->optlen += doffset+3;
+ dopt->is_strictroute = sopt->is_strictroute;
+ }
+ }
+ while (dopt->optlen & 3) {
+ *dptr++ = IPOPT_END;
+ dopt->optlen++;
+ }
+ return 0;
+}
+
+/*
+ * Options "fragmenting", just fill options not
+ * allowed in fragments with NOOPs.
+ * Simple and stupid 8), but the most efficient way.
+ */
+
+void ip_options_fragment(struct sk_buff * skb)
+{
+ unsigned char * optptr = skb->nh.raw;
+ struct ip_options * opt = &(IPCB(skb)->opt);
+ int l = opt->optlen;
+ int optlen;
+
+ while (l > 0) {
+ switch (*optptr) {
+ case IPOPT_END:
+ return;
+ case IPOPT_NOOP:
+ l--;
+ optptr++;
+ continue;
+ }
+ optlen = optptr[1];
+ if (optlen<2 || optlen>l)
+ return;
+ if (!IPOPT_COPIED(*optptr))
+ memset(optptr, IPOPT_NOOP, optlen);
+ l -= optlen;
+ optptr += optlen;
+ }
+ opt->ts = 0;
+ opt->rr = 0;
+ opt->rr_needaddr = 0;
+ opt->ts_needaddr = 0;
+ opt->ts_needtime = 0;
+ return;
+}
+
+/*
+ * Verify options and fill pointers in struct options.
+ * Caller should clear *opt, and set opt->data.
+ * If opt == NULL, then skb->data should point to IP header.
+ */
+
+int ip_options_compile(struct ip_options * opt, struct sk_buff * skb)
+{
+ int l;
+ unsigned char * iph;
+ unsigned char * optptr;
+ int optlen;
+ unsigned char * pp_ptr = NULL;
+ struct rtable *rt = skb ? (struct rtable*)skb->dst : NULL;
+
+ if (!opt) {
+ opt = &(IPCB(skb)->opt);
+ memset(opt, 0, sizeof(struct ip_options));
+ iph = skb->nh.raw;
+ opt->optlen = ((struct iphdr *)iph)->ihl*4 - sizeof(struct iphdr);
+ optptr = iph + sizeof(struct iphdr);
+ opt->is_data = 0;
+ } else {
+ optptr = opt->is_data ? opt->__data : (unsigned char*)&(skb->nh.iph[1]);
+ iph = optptr - sizeof(struct iphdr);
+ }
+
+ for (l = opt->optlen; l > 0; ) {
+ switch (*optptr) {
+ case IPOPT_END:
+ for (optptr++, l--; l>0; optptr++, l--) {
+ if (*optptr != IPOPT_END) {
+ *optptr = IPOPT_END;
+ opt->is_changed = 1;
+ }
+ }
+ goto eol;
+ case IPOPT_NOOP:
+ l--;
+ optptr++;
+ continue;
+ }
+ optlen = optptr[1];
+ if (optlen<2 || optlen>l) {
+ pp_ptr = optptr;
+ goto error;
+ }
+ switch (*optptr) {
+ case IPOPT_SSRR:
+ case IPOPT_LSRR:
+ if (optlen < 3) {
+ pp_ptr = optptr + 1;
+ goto error;
+ }
+ if (optptr[2] < 4) {
+ pp_ptr = optptr + 2;
+ goto error;
+ }
+ /* NB: cf RFC-1812 5.2.4.1 */
+ if (opt->srr) {
+ pp_ptr = optptr;
+ goto error;
+ }
+ if (!skb) {
+ if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) {
+ pp_ptr = optptr + 1;
+ goto error;
+ }
+ memcpy(&opt->faddr, &optptr[3], 4);
+ if (optlen > 7)
+ memmove(&optptr[3], &optptr[7], optlen-7);
+ }
+ opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
+ opt->srr = optptr - iph;
+ break;
+ case IPOPT_RR:
+ if (opt->rr) {
+ pp_ptr = optptr;
+ goto error;
+ }
+ if (optlen < 3) {
+ pp_ptr = optptr + 1;
+ goto error;
+ }
+ if (optptr[2] < 4) {
+ pp_ptr = optptr + 2;
+ goto error;
+ }
+ if (optptr[2] <= optlen) {
+ if (optptr[2]+3 > optlen) {
+ pp_ptr = optptr + 2;
+ goto error;
+ }
+ if (skb) {
+ memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
+ opt->is_changed = 1;
+ }
+ optptr[2] += 4;
+ opt->rr_needaddr = 1;
+ }
+ opt->rr = optptr - iph;
+ break;
+ case IPOPT_TIMESTAMP:
+ if (opt->ts) {
+ pp_ptr = optptr;
+ goto error;
+ }
+ if (optlen < 4) {
+ pp_ptr = optptr + 1;
+ goto error;
+ }
+ if (optptr[2] < 5) {
+ pp_ptr = optptr + 2;
+ goto error;
+ }
+ if (optptr[2] <= optlen) {
+ __u32 * timeptr = NULL;
+ if (optptr[2]+3 > optptr[1]) {
+ pp_ptr = optptr + 2;
+ goto error;
+ }
+ switch (optptr[3]&0xF) {
+ case IPOPT_TS_TSONLY:
+ opt->ts = optptr - iph;
+ if (skb)
+ timeptr = (__u32*)&optptr[optptr[2]-1];
+ opt->ts_needtime = 1;
+ optptr[2] += 4;
+ break;
+ case IPOPT_TS_TSANDADDR:
+ if (optptr[2]+7 > optptr[1]) {
+ pp_ptr = optptr + 2;
+ goto error;
+ }
+ opt->ts = optptr - iph;
+ if (skb) {
+ memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
+ timeptr = (__u32*)&optptr[optptr[2]+3];
+ }
+ opt->ts_needaddr = 1;
+ opt->ts_needtime = 1;
+ optptr[2] += 8;
+ break;
+ case IPOPT_TS_PRESPEC:
+ if (optptr[2]+7 > optptr[1]) {
+ pp_ptr = optptr + 2;
+ goto error;
+ }
+ opt->ts = optptr - iph;
+ {
+ u32 addr;
+ memcpy(&addr, &optptr[optptr[2]-1], 4);
+ if (inet_addr_type(addr) == RTN_UNICAST)
+ break;
+ if (skb)
+ timeptr = (__u32*)&optptr[optptr[2]+3];
+ }
+ opt->ts_needtime = 1;
+ optptr[2] += 8;
+ break;
+ default:
+ if (!skb && !capable(CAP_NET_RAW)) {
+ pp_ptr = optptr + 3;
+ goto error;
+ }
+ break;
+ }
+ if (timeptr) {
+ struct timeval tv;
+ __u32 midtime;
+ do_gettimeofday(&tv);
+ midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
+ memcpy(timeptr, &midtime, sizeof(__u32));
+ opt->is_changed = 1;
+ }
+ } else {
+ unsigned overflow = optptr[3]>>4;
+ if (overflow == 15) {
+ pp_ptr = optptr + 3;
+ goto error;
+ }
+ opt->ts = optptr - iph;
+ if (skb) {
+ optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4);
+ opt->is_changed = 1;
+ }
+ }
+ break;
+ case IPOPT_RA:
+ if (optlen < 4) {
+ pp_ptr = optptr + 1;
+ goto error;
+ }
+ if (optptr[2] == 0 && optptr[3] == 0)
+ opt->router_alert = optptr - iph;
+ break;
+ case IPOPT_SEC:
+ case IPOPT_SID:
+ default:
+ if (!skb && !capable(CAP_NET_RAW)) {
+ pp_ptr = optptr;
+ goto error;
+ }
+ break;
+ }
+ l -= optlen;
+ optptr += optlen;
+ }
+
+eol:
+ if (!pp_ptr)
+ return 0;
+
+error:
+ if (skb) {
+ icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
+ }
+ return -EINVAL;
+}
+
+
+/*
+ * Undo all the changes done by ip_options_compile().
+ */
+
+void ip_options_undo(struct ip_options * opt)
+{
+ if (opt->srr) {
+ unsigned char * optptr = opt->__data+opt->srr-sizeof(struct iphdr);
+ memmove(optptr+7, optptr+3, optptr[1]-7);
+ memcpy(optptr+3, &opt->faddr, 4);
+ }
+ if (opt->rr_needaddr) {
+ unsigned char * optptr = opt->__data+opt->rr-sizeof(struct iphdr);
+ optptr[2] -= 4;
+ memset(&optptr[optptr[2]-1], 0, 4);
+ }
+ if (opt->ts) {
+ unsigned char * optptr = opt->__data+opt->ts-sizeof(struct iphdr);
+ if (opt->ts_needtime) {
+ optptr[2] -= 4;
+ memset(&optptr[optptr[2]-1], 0, 4);
+ if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
+ optptr[2] -= 4;
+ }
+ if (opt->ts_needaddr) {
+ optptr[2] -= 4;
+ memset(&optptr[optptr[2]-1], 0, 4);
+ }
+ }
+}
+
+int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen, int user)
+{
+ struct ip_options *opt;
+
+ opt = kmalloc(sizeof(struct ip_options)+((optlen+3)&~3), GFP_KERNEL);
+ if (!opt)
+ return -ENOMEM;
+ memset(opt, 0, sizeof(struct ip_options));
+ if (optlen) {
+ if (user) {
+ if (copy_from_user(opt->__data, data, optlen)) {
+ kfree(opt);
+ return -EFAULT;
+ }
+ } else
+ memcpy(opt->__data, data, optlen);
+ }
+ while (optlen & 3)
+ opt->__data[optlen++] = IPOPT_END;
+ opt->optlen = optlen;
+ opt->is_data = 1;
+ opt->is_setbyuser = 1;
+ if (optlen && ip_options_compile(opt, NULL)) {
+ kfree(opt);
+ return -EINVAL;
+ }
+ if (*optp)
+ kfree(*optp);
+ *optp = opt;
+ return 0;
+}
+
+void ip_forward_options(struct sk_buff *skb)
+{
+ struct ip_options * opt = &(IPCB(skb)->opt);
+ unsigned char * optptr;
+ struct rtable *rt = (struct rtable*)skb->dst;
+ unsigned char *raw = skb->nh.raw;
+
+ if (opt->rr_needaddr) {
+ optptr = (unsigned char *)raw + opt->rr;
+ ip_rt_get_source(&optptr[optptr[2]-5], rt);
+ opt->is_changed = 1;
+ }
+ if (opt->srr_is_hit) {
+ int srrptr, srrspace;
+
+ optptr = raw + opt->srr;
+
+ for ( srrptr=optptr[2], srrspace = optptr[1];
+ srrptr <= srrspace;
+ srrptr += 4
+ ) {
+ if (srrptr + 3 > srrspace)
+ break;
+ if (memcmp(&rt->rt_dst, &optptr[srrptr-1], 4) == 0)
+ break;
+ }
+ if (srrptr + 3 <= srrspace) {
+ opt->is_changed = 1;
+ ip_rt_get_source(&optptr[srrptr-1], rt);
+ skb->nh.iph->daddr = rt->rt_dst;
+ optptr[2] = srrptr+4;
+ } else if (net_ratelimit())
+ printk(KERN_CRIT "ip_forward(): Argh! Destination lost!\n");
+ if (opt->ts_needaddr) {
+ optptr = raw + opt->ts;
+ ip_rt_get_source(&optptr[optptr[2]-9], rt);
+ opt->is_changed = 1;
+ }
+ }
+ if (opt->is_changed) {
+ opt->is_changed = 0;
+ ip_send_check(skb->nh.iph);
+ }
+}
+
+int ip_options_rcv_srr(struct sk_buff *skb)
+{
+ struct ip_options *opt = &(IPCB(skb)->opt);
+ int srrspace, srrptr;
+ u32 nexthop;
+ struct iphdr *iph = skb->nh.iph;
+ unsigned char * optptr = skb->nh.raw + opt->srr;
+ struct rtable *rt = (struct rtable*)skb->dst;
+ struct rtable *rt2;
+ int err;
+
+ if (!opt->srr)
+ return 0;
+
+ if (skb->pkt_type != PACKET_HOST)
+ return -EINVAL;
+ if (rt->rt_type == RTN_UNICAST) {
+ if (!opt->is_strictroute)
+ return 0;
+ icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
+ return -EINVAL;
+ }
+ if (rt->rt_type != RTN_LOCAL)
+ return -EINVAL;
+
+ for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) {
+ if (srrptr + 3 > srrspace) {
+ icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24));
+ return -EINVAL;
+ }
+ memcpy(&nexthop, &optptr[srrptr-1], 4);
+
+ rt = (struct rtable*)skb->dst;
+ skb->dst = NULL;
+ err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
+ rt2 = (struct rtable*)skb->dst;
+ if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
+ ip_rt_put(rt2);
+ skb->dst = &rt->u.dst;
+ return -EINVAL;
+ }
+ ip_rt_put(rt);
+ if (rt2->rt_type != RTN_LOCAL)
+ break;
+ /* Superfast 8) loopback forward */
+ memcpy(&iph->daddr, &optptr[srrptr-1], 4);
+ opt->is_changed = 1;
+ }
+ if (srrptr <= srrspace) {
+ opt->srr_is_hit = 1;
+ opt->is_changed = 1;
+ }
+ return 0;
+}
+
+EXPORT_SYMBOL(ip_options_compile);
+EXPORT_SYMBOL(ip_options_undo);
OpenPOWER on IntegriCloud