mirror of https://gitee.com/openkylin/linux.git
666 lines
15 KiB
C
666 lines
15 KiB
C
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* The options processing module for ip.c
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*
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* Authors: A.N.Kuznetsov
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*
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*/
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#define pr_fmt(fmt) "IPv4: " fmt
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#include <linux/capability.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <asm/uaccess.h>
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#include <asm/unaligned.h>
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#include <linux/skbuff.h>
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#include <linux/ip.h>
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#include <linux/icmp.h>
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#include <linux/netdevice.h>
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#include <linux/rtnetlink.h>
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#include <net/sock.h>
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#include <net/ip.h>
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#include <net/icmp.h>
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#include <net/route.h>
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#include <net/cipso_ipv4.h>
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#include <net/ip_fib.h>
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/*
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* Write options to IP header, record destination address to
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* source route option, address of outgoing interface
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* (we should already know it, so that this function is allowed be
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* called only after routing decision) and timestamp,
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* if we originate this datagram.
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*
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* daddr is real destination address, next hop is recorded in IP header.
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* saddr is address of outgoing interface.
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*/
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void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
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__be32 daddr, struct rtable *rt, int is_frag)
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{
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unsigned char *iph = skb_network_header(skb);
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memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options));
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memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
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opt = &(IPCB(skb)->opt);
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if (opt->srr)
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memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);
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if (!is_frag) {
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if (opt->rr_needaddr)
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ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, skb, rt);
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if (opt->ts_needaddr)
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ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, skb, rt);
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if (opt->ts_needtime) {
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struct timespec tv;
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__be32 midtime;
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getnstimeofday(&tv);
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midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC);
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memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
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}
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return;
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}
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if (opt->rr) {
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memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
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opt->rr = 0;
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opt->rr_needaddr = 0;
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}
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if (opt->ts) {
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memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
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opt->ts = 0;
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opt->ts_needaddr = opt->ts_needtime = 0;
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}
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}
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/*
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* Provided (sopt, skb) points to received options,
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* build in dopt compiled option set appropriate for answering.
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* i.e. invert SRR option, copy anothers,
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* and grab room in RR/TS options.
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*
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* NOTE: dopt cannot point to skb.
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*/
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int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb)
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{
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const struct ip_options *sopt;
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unsigned char *sptr, *dptr;
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int soffset, doffset;
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int optlen;
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memset(dopt, 0, sizeof(struct ip_options));
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sopt = &(IPCB(skb)->opt);
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if (sopt->optlen == 0)
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return 0;
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sptr = skb_network_header(skb);
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dptr = dopt->__data;
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if (sopt->rr) {
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optlen = sptr[sopt->rr+1];
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soffset = sptr[sopt->rr+2];
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dopt->rr = dopt->optlen + sizeof(struct iphdr);
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memcpy(dptr, sptr+sopt->rr, optlen);
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if (sopt->rr_needaddr && soffset <= optlen) {
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if (soffset + 3 > optlen)
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return -EINVAL;
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dptr[2] = soffset + 4;
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dopt->rr_needaddr = 1;
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}
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dptr += optlen;
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dopt->optlen += optlen;
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}
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if (sopt->ts) {
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optlen = sptr[sopt->ts+1];
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soffset = sptr[sopt->ts+2];
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dopt->ts = dopt->optlen + sizeof(struct iphdr);
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memcpy(dptr, sptr+sopt->ts, optlen);
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if (soffset <= optlen) {
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if (sopt->ts_needaddr) {
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if (soffset + 3 > optlen)
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return -EINVAL;
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dopt->ts_needaddr = 1;
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soffset += 4;
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}
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if (sopt->ts_needtime) {
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if (soffset + 3 > optlen)
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return -EINVAL;
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if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) {
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dopt->ts_needtime = 1;
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soffset += 4;
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} else {
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dopt->ts_needtime = 0;
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if (soffset + 7 <= optlen) {
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__be32 addr;
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memcpy(&addr, dptr+soffset-1, 4);
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if (inet_addr_type(dev_net(skb_dst(skb)->dev), addr) != RTN_UNICAST) {
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dopt->ts_needtime = 1;
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soffset += 8;
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}
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}
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}
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}
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dptr[2] = soffset;
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}
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dptr += optlen;
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dopt->optlen += optlen;
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}
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if (sopt->srr) {
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unsigned char *start = sptr+sopt->srr;
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__be32 faddr;
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optlen = start[1];
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soffset = start[2];
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doffset = 0;
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if (soffset > optlen)
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soffset = optlen + 1;
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soffset -= 4;
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if (soffset > 3) {
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memcpy(&faddr, &start[soffset-1], 4);
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for (soffset -= 4, doffset = 4; soffset > 3; soffset -= 4, doffset += 4)
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memcpy(&dptr[doffset-1], &start[soffset-1], 4);
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/*
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* RFC1812 requires to fix illegal source routes.
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*/
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if (memcmp(&ip_hdr(skb)->saddr,
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&start[soffset + 3], 4) == 0)
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doffset -= 4;
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}
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if (doffset > 3) {
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__be32 daddr = fib_compute_spec_dst(skb);
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memcpy(&start[doffset-1], &daddr, 4);
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dopt->faddr = faddr;
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dptr[0] = start[0];
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dptr[1] = doffset+3;
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dptr[2] = 4;
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dptr += doffset+3;
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dopt->srr = dopt->optlen + sizeof(struct iphdr);
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dopt->optlen += doffset+3;
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dopt->is_strictroute = sopt->is_strictroute;
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}
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}
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if (sopt->cipso) {
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optlen = sptr[sopt->cipso+1];
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dopt->cipso = dopt->optlen+sizeof(struct iphdr);
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memcpy(dptr, sptr+sopt->cipso, optlen);
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dptr += optlen;
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dopt->optlen += optlen;
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}
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while (dopt->optlen & 3) {
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*dptr++ = IPOPT_END;
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dopt->optlen++;
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}
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return 0;
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}
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/*
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* Options "fragmenting", just fill options not
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* allowed in fragments with NOOPs.
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* Simple and stupid 8), but the most efficient way.
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*/
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void ip_options_fragment(struct sk_buff *skb)
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{
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unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr);
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struct ip_options *opt = &(IPCB(skb)->opt);
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int l = opt->optlen;
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int optlen;
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while (l > 0) {
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switch (*optptr) {
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case IPOPT_END:
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return;
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case IPOPT_NOOP:
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l--;
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optptr++;
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continue;
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}
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optlen = optptr[1];
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if (optlen < 2 || optlen > l)
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return;
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if (!IPOPT_COPIED(*optptr))
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memset(optptr, IPOPT_NOOP, optlen);
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l -= optlen;
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optptr += optlen;
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}
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opt->ts = 0;
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opt->rr = 0;
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opt->rr_needaddr = 0;
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opt->ts_needaddr = 0;
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opt->ts_needtime = 0;
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}
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/* helper used by ip_options_compile() to call fib_compute_spec_dst()
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* at most one time.
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*/
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static void spec_dst_fill(__be32 *spec_dst, struct sk_buff *skb)
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{
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if (*spec_dst == htonl(INADDR_ANY))
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*spec_dst = fib_compute_spec_dst(skb);
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}
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/*
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* Verify options and fill pointers in struct options.
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* Caller should clear *opt, and set opt->data.
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* If opt == NULL, then skb->data should point to IP header.
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*/
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int ip_options_compile(struct net *net,
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struct ip_options *opt, struct sk_buff *skb)
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{
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__be32 spec_dst = htonl(INADDR_ANY);
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unsigned char *pp_ptr = NULL;
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struct rtable *rt = NULL;
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unsigned char *optptr;
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unsigned char *iph;
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int optlen, l;
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if (skb != NULL) {
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rt = skb_rtable(skb);
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optptr = (unsigned char *)&(ip_hdr(skb)[1]);
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} else
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optptr = opt->__data;
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iph = optptr - sizeof(struct iphdr);
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for (l = opt->optlen; l > 0; ) {
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switch (*optptr) {
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case IPOPT_END:
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for (optptr++, l--; l > 0; optptr++, l--) {
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if (*optptr != IPOPT_END) {
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*optptr = IPOPT_END;
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opt->is_changed = 1;
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}
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}
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goto eol;
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case IPOPT_NOOP:
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l--;
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optptr++;
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continue;
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}
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if (unlikely(l < 2)) {
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pp_ptr = optptr;
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goto error;
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}
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optlen = optptr[1];
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if (optlen < 2 || optlen > l) {
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pp_ptr = optptr;
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goto error;
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}
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switch (*optptr) {
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case IPOPT_SSRR:
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case IPOPT_LSRR:
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if (optlen < 3) {
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pp_ptr = optptr + 1;
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goto error;
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}
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if (optptr[2] < 4) {
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pp_ptr = optptr + 2;
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goto error;
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}
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/* NB: cf RFC-1812 5.2.4.1 */
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if (opt->srr) {
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pp_ptr = optptr;
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goto error;
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}
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if (!skb) {
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if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) {
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pp_ptr = optptr + 1;
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goto error;
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}
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memcpy(&opt->faddr, &optptr[3], 4);
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if (optlen > 7)
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memmove(&optptr[3], &optptr[7], optlen-7);
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}
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opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
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opt->srr = optptr - iph;
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break;
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case IPOPT_RR:
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if (opt->rr) {
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pp_ptr = optptr;
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goto error;
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}
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if (optlen < 3) {
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pp_ptr = optptr + 1;
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goto error;
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}
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if (optptr[2] < 4) {
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pp_ptr = optptr + 2;
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goto error;
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}
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if (optptr[2] <= optlen) {
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if (optptr[2]+3 > optlen) {
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pp_ptr = optptr + 2;
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goto error;
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}
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if (rt) {
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spec_dst_fill(&spec_dst, skb);
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memcpy(&optptr[optptr[2]-1], &spec_dst, 4);
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opt->is_changed = 1;
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}
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optptr[2] += 4;
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opt->rr_needaddr = 1;
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}
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opt->rr = optptr - iph;
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break;
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case IPOPT_TIMESTAMP:
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if (opt->ts) {
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pp_ptr = optptr;
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goto error;
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}
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if (optlen < 4) {
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pp_ptr = optptr + 1;
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goto error;
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}
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if (optptr[2] < 5) {
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pp_ptr = optptr + 2;
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goto error;
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}
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if (optptr[2] <= optlen) {
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unsigned char *timeptr = NULL;
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if (optptr[2]+3 > optlen) {
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pp_ptr = optptr + 2;
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goto error;
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}
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switch (optptr[3]&0xF) {
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case IPOPT_TS_TSONLY:
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if (skb)
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timeptr = &optptr[optptr[2]-1];
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opt->ts_needtime = 1;
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optptr[2] += 4;
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break;
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case IPOPT_TS_TSANDADDR:
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if (optptr[2]+7 > optlen) {
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pp_ptr = optptr + 2;
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goto error;
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}
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if (rt) {
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spec_dst_fill(&spec_dst, skb);
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memcpy(&optptr[optptr[2]-1], &spec_dst, 4);
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timeptr = &optptr[optptr[2]+3];
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}
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opt->ts_needaddr = 1;
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opt->ts_needtime = 1;
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optptr[2] += 8;
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break;
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case IPOPT_TS_PRESPEC:
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if (optptr[2]+7 > optlen) {
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pp_ptr = optptr + 2;
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goto error;
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}
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{
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__be32 addr;
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memcpy(&addr, &optptr[optptr[2]-1], 4);
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if (inet_addr_type(net, addr) == RTN_UNICAST)
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break;
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if (skb)
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timeptr = &optptr[optptr[2]+3];
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}
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opt->ts_needtime = 1;
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optptr[2] += 8;
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break;
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default:
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if (!skb && !ns_capable(net->user_ns, CAP_NET_RAW)) {
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pp_ptr = optptr + 3;
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goto error;
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}
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break;
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}
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if (timeptr) {
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struct timespec tv;
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u32 midtime;
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getnstimeofday(&tv);
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midtime = (tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC;
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put_unaligned_be32(midtime, timeptr);
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opt->is_changed = 1;
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}
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} else if ((optptr[3]&0xF) != IPOPT_TS_PRESPEC) {
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unsigned int overflow = optptr[3]>>4;
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if (overflow == 15) {
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pp_ptr = optptr + 3;
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goto error;
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}
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if (skb) {
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optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4);
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opt->is_changed = 1;
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}
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}
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opt->ts = optptr - iph;
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break;
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case IPOPT_RA:
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if (optlen < 4) {
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pp_ptr = optptr + 1;
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goto error;
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}
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if (optptr[2] == 0 && optptr[3] == 0)
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opt->router_alert = optptr - iph;
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break;
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case IPOPT_CIPSO:
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if ((!skb && !ns_capable(net->user_ns, CAP_NET_RAW)) || opt->cipso) {
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pp_ptr = optptr;
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goto error;
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}
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opt->cipso = optptr - iph;
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if (cipso_v4_validate(skb, &optptr)) {
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pp_ptr = optptr;
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goto error;
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}
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break;
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case IPOPT_SEC:
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case IPOPT_SID:
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default:
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if (!skb && !ns_capable(net->user_ns, CAP_NET_RAW)) {
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pp_ptr = optptr;
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goto error;
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}
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break;
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}
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l -= optlen;
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optptr += optlen;
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}
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eol:
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if (!pp_ptr)
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return 0;
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error:
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if (skb) {
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icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
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}
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return -EINVAL;
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}
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EXPORT_SYMBOL(ip_options_compile);
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/*
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* Undo all the changes done by ip_options_compile().
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*/
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void ip_options_undo(struct ip_options *opt)
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{
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if (opt->srr) {
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unsigned char *optptr = opt->__data+opt->srr-sizeof(struct iphdr);
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memmove(optptr+7, optptr+3, optptr[1]-7);
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memcpy(optptr+3, &opt->faddr, 4);
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}
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if (opt->rr_needaddr) {
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unsigned char *optptr = opt->__data+opt->rr-sizeof(struct iphdr);
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optptr[2] -= 4;
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memset(&optptr[optptr[2]-1], 0, 4);
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}
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if (opt->ts) {
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unsigned char *optptr = opt->__data+opt->ts-sizeof(struct iphdr);
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if (opt->ts_needtime) {
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optptr[2] -= 4;
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memset(&optptr[optptr[2]-1], 0, 4);
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if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
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optptr[2] -= 4;
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}
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if (opt->ts_needaddr) {
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optptr[2] -= 4;
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memset(&optptr[optptr[2]-1], 0, 4);
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}
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}
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}
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static struct ip_options_rcu *ip_options_get_alloc(const int optlen)
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{
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return kzalloc(sizeof(struct ip_options_rcu) + ((optlen + 3) & ~3),
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GFP_KERNEL);
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}
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static int ip_options_get_finish(struct net *net, struct ip_options_rcu **optp,
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struct ip_options_rcu *opt, int optlen)
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{
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while (optlen & 3)
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opt->opt.__data[optlen++] = IPOPT_END;
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opt->opt.optlen = optlen;
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if (optlen && ip_options_compile(net, &opt->opt, NULL)) {
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kfree(opt);
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return -EINVAL;
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}
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kfree(*optp);
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*optp = opt;
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return 0;
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}
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int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
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unsigned char __user *data, int optlen)
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{
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struct ip_options_rcu *opt = ip_options_get_alloc(optlen);
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if (!opt)
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return -ENOMEM;
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if (optlen && copy_from_user(opt->opt.__data, data, optlen)) {
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kfree(opt);
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return -EFAULT;
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}
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return ip_options_get_finish(net, optp, opt, optlen);
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}
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int ip_options_get(struct net *net, struct ip_options_rcu **optp,
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unsigned char *data, int optlen)
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{
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struct ip_options_rcu *opt = ip_options_get_alloc(optlen);
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if (!opt)
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return -ENOMEM;
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if (optlen)
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memcpy(opt->opt.__data, data, optlen);
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return ip_options_get_finish(net, optp, opt, optlen);
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}
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void ip_forward_options(struct sk_buff *skb)
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{
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struct ip_options *opt = &(IPCB(skb)->opt);
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unsigned char *optptr;
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struct rtable *rt = skb_rtable(skb);
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unsigned char *raw = skb_network_header(skb);
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if (opt->rr_needaddr) {
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optptr = (unsigned char *)raw + opt->rr;
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ip_rt_get_source(&optptr[optptr[2]-5], skb, rt);
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opt->is_changed = 1;
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}
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if (opt->srr_is_hit) {
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int srrptr, srrspace;
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optptr = raw + opt->srr;
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for ( srrptr = optptr[2], srrspace = optptr[1];
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srrptr <= srrspace;
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srrptr += 4
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) {
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if (srrptr + 3 > srrspace)
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break;
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if (memcmp(&opt->nexthop, &optptr[srrptr-1], 4) == 0)
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break;
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}
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if (srrptr + 3 <= srrspace) {
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opt->is_changed = 1;
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ip_hdr(skb)->daddr = opt->nexthop;
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ip_rt_get_source(&optptr[srrptr-1], skb, rt);
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optptr[2] = srrptr+4;
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} else {
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net_crit_ratelimited("%s(): Argh! Destination lost!\n",
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__func__);
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}
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if (opt->ts_needaddr) {
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optptr = raw + opt->ts;
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ip_rt_get_source(&optptr[optptr[2]-9], skb, rt);
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opt->is_changed = 1;
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}
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}
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if (opt->is_changed) {
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opt->is_changed = 0;
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ip_send_check(ip_hdr(skb));
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}
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}
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int ip_options_rcv_srr(struct sk_buff *skb)
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{
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struct ip_options *opt = &(IPCB(skb)->opt);
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int srrspace, srrptr;
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__be32 nexthop;
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struct iphdr *iph = ip_hdr(skb);
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unsigned char *optptr = skb_network_header(skb) + opt->srr;
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struct rtable *rt = skb_rtable(skb);
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struct rtable *rt2;
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unsigned long orefdst;
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int err;
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if (!rt)
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return 0;
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if (skb->pkt_type != PACKET_HOST)
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return -EINVAL;
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if (rt->rt_type == RTN_UNICAST) {
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if (!opt->is_strictroute)
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return 0;
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icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
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return -EINVAL;
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}
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if (rt->rt_type != RTN_LOCAL)
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return -EINVAL;
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for (srrptr = optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) {
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if (srrptr + 3 > srrspace) {
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icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24));
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return -EINVAL;
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}
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|
memcpy(&nexthop, &optptr[srrptr-1], 4);
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orefdst = skb->_skb_refdst;
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|
skb_dst_set(skb, NULL);
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err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
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rt2 = skb_rtable(skb);
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|
if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
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|
skb_dst_drop(skb);
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skb->_skb_refdst = orefdst;
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|
return -EINVAL;
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|
}
|
|
refdst_drop(orefdst);
|
|
if (rt2->rt_type != RTN_LOCAL)
|
|
break;
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|
/* Superfast 8) loopback forward */
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|
iph->daddr = nexthop;
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|
opt->is_changed = 1;
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|
}
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|
if (srrptr <= srrspace) {
|
|
opt->srr_is_hit = 1;
|
|
opt->nexthop = nexthop;
|
|
opt->is_changed = 1;
|
|
}
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|
return 0;
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|
}
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EXPORT_SYMBOL(ip_options_rcv_srr);
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