/* * IPv6 output functions * Linux INET6 implementation * * Authors: * Pedro Roque * * $Id: ip6_output.c,v 1.34 2002/02/01 22:01:04 davem Exp $ * * Based on linux/net/ipv4/ip_output.c * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Changes: * A.N.Kuznetsov : airthmetics in fragmentation. * extension headers are implemented. * route changes now work. * ip6_forward does not confuse sniffers. * etc. * * H. von Brand : Added missing #include * Imran Patel : frag id should be in NBO * Kazunori MIYAZAWA @USAGI * : add ip6_append_data and related functions * for datagram xmit */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)); static __inline__ void ipv6_select_ident(struct sk_buff *skb, struct frag_hdr *fhdr) { static u32 ipv6_fragmentation_id = 1; static DEFINE_SPINLOCK(ip6_id_lock); spin_lock_bh(&ip6_id_lock); fhdr->identification = htonl(ipv6_fragmentation_id); if (++ipv6_fragmentation_id == 0) ipv6_fragmentation_id = 1; spin_unlock_bh(&ip6_id_lock); } static int ip6_output_finish(struct sk_buff *skb) { struct dst_entry *dst = skb->dst; if (dst->hh) return neigh_hh_output(dst->hh, skb); else if (dst->neighbour) return dst->neighbour->output(skb); IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES); kfree_skb(skb); return -EINVAL; } /* dev_loopback_xmit for use with netfilter. */ static int ip6_dev_loopback_xmit(struct sk_buff *newskb) { skb_reset_mac_header(newskb); __skb_pull(newskb, skb_network_offset(newskb)); newskb->pkt_type = PACKET_LOOPBACK; newskb->ip_summed = CHECKSUM_UNNECESSARY; BUG_TRAP(newskb->dst); netif_rx(newskb); return 0; } static int ip6_output2(struct sk_buff *skb) { struct dst_entry *dst = skb->dst; struct net_device *dev = dst->dev; skb->protocol = htons(ETH_P_IPV6); skb->dev = dev; if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) { struct ipv6_pinfo* np = skb->sk ? inet6_sk(skb->sk) : NULL; struct inet6_dev *idev = ip6_dst_idev(skb->dst); if (!(dev->flags & IFF_LOOPBACK) && (!np || np->mc_loop) && ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr, &ipv6_hdr(skb)->saddr)) { struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); /* Do not check for IFF_ALLMULTI; multicast routing is not supported in any case. */ if (newskb) NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, newskb, NULL, newskb->dev, ip6_dev_loopback_xmit); if (ipv6_hdr(skb)->hop_limit == 0) { IP6_INC_STATS(idev, IPSTATS_MIB_OUTDISCARDS); kfree_skb(skb); return 0; } } IP6_INC_STATS(idev, IPSTATS_MIB_OUTMCASTPKTS); } return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb,NULL, skb->dev,ip6_output_finish); } static inline int ip6_skb_dst_mtu(struct sk_buff *skb) { struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; return (np && np->pmtudisc == IPV6_PMTUDISC_PROBE) ? skb->dst->dev->mtu : dst_mtu(skb->dst); } int ip6_output(struct sk_buff *skb) { if ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) || dst_allfrag(skb->dst)) return ip6_fragment(skb, ip6_output2); else return ip6_output2(skb); } /* * xmit an sk_buff (used by TCP) */ int ip6_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl, struct ipv6_txoptions *opt, int ipfragok) { struct ipv6_pinfo *np = inet6_sk(sk); struct in6_addr *first_hop = &fl->fl6_dst; struct dst_entry *dst = skb->dst; struct ipv6hdr *hdr; u8 proto = fl->proto; int seg_len = skb->len; int hlimit, tclass; u32 mtu; if (opt) { unsigned int head_room; /* First: exthdrs may take lots of space (~8K for now) MAX_HEADER is not enough. */ head_room = opt->opt_nflen + opt->opt_flen; seg_len += head_room; head_room += sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev); if (skb_headroom(skb) < head_room) { struct sk_buff *skb2 = skb_realloc_headroom(skb, head_room); if (skb2 == NULL) { IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_OUTDISCARDS); kfree_skb(skb); return -ENOBUFS; } kfree_skb(skb); skb = skb2; if (sk) skb_set_owner_w(skb, sk); } if (opt->opt_flen) ipv6_push_frag_opts(skb, opt, &proto); if (opt->opt_nflen) ipv6_push_nfrag_opts(skb, opt, &proto, &first_hop); } skb_push(skb, sizeof(struct ipv6hdr)); skb_reset_network_header(skb); hdr = ipv6_hdr(skb); /* * Fill in the IPv6 header */ hlimit = -1; if (np) hlimit = np->hop_limit; if (hlimit < 0) hlimit = dst_metric(dst, RTAX_HOPLIMIT); if (hlimit < 0) hlimit = ipv6_get_hoplimit(dst->dev); tclass = -1; if (np) tclass = np->tclass; if (tclass < 0) tclass = 0; *(__be32 *)hdr = htonl(0x60000000 | (tclass << 20)) | fl->fl6_flowlabel; hdr->payload_len = htons(seg_len); hdr->nexthdr = proto; hdr->hop_limit = hlimit; ipv6_addr_copy(&hdr->saddr, &fl->fl6_src); ipv6_addr_copy(&hdr->daddr, first_hop); skb->priority = sk->sk_priority; mtu = dst_mtu(dst); if ((skb->len <= mtu) || ipfragok || skb_is_gso(skb)) { IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_OUTREQUESTS); return NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, dst->dev, dst_output); } if (net_ratelimit()) printk(KERN_DEBUG "IPv6: sending pkt_too_big to self\n"); skb->dev = dst->dev; icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev); IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS); kfree_skb(skb); return -EMSGSIZE; } EXPORT_SYMBOL(ip6_xmit); /* * To avoid extra problems ND packets are send through this * routine. It's code duplication but I really want to avoid * extra checks since ipv6_build_header is used by TCP (which * is for us performance critical) */ int ip6_nd_hdr(struct sock *sk, struct sk_buff *skb, struct net_device *dev, struct in6_addr *saddr, struct in6_addr *daddr, int proto, int len) { struct ipv6_pinfo *np = inet6_sk(sk); struct ipv6hdr *hdr; int totlen; skb->protocol = htons(ETH_P_IPV6); skb->dev = dev; totlen = len + sizeof(struct ipv6hdr); skb_reset_network_header(skb); skb_put(skb, sizeof(struct ipv6hdr)); hdr = ipv6_hdr(skb); *(__be32*)hdr = htonl(0x60000000); hdr->payload_len = htons(len); hdr->nexthdr = proto; hdr->hop_limit = np->hop_limit; ipv6_addr_copy(&hdr->saddr, saddr); ipv6_addr_copy(&hdr->daddr, daddr); return 0; } static int ip6_call_ra_chain(struct sk_buff *skb, int sel) { struct ip6_ra_chain *ra; struct sock *last = NULL; read_lock(&ip6_ra_lock); for (ra = ip6_ra_chain; ra; ra = ra->next) { struct sock *sk = ra->sk; if (sk && ra->sel == sel && (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == skb->dev->ifindex)) { if (last) { struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC); if (skb2) rawv6_rcv(last, skb2); } last = sk; } } if (last) { rawv6_rcv(last, skb); read_unlock(&ip6_ra_lock); return 1; } read_unlock(&ip6_ra_lock); return 0; } static int ip6_forward_proxy_check(struct sk_buff *skb) { struct ipv6hdr *hdr = ipv6_hdr(skb); u8 nexthdr = hdr->nexthdr; int offset; if (ipv6_ext_hdr(nexthdr)) { offset = ipv6_skip_exthdr(skb, sizeof(*hdr), &nexthdr); if (offset < 0) return 0; } else offset = sizeof(struct ipv6hdr); if (nexthdr == IPPROTO_ICMPV6) { struct icmp6hdr *icmp6; if (!pskb_may_pull(skb, (skb_network_header(skb) + offset + 1 - skb->data))) return 0; icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset); switch (icmp6->icmp6_type) { case NDISC_ROUTER_SOLICITATION: case NDISC_ROUTER_ADVERTISEMENT: case NDISC_NEIGHBOUR_SOLICITATION: case NDISC_NEIGHBOUR_ADVERTISEMENT: case NDISC_REDIRECT: /* For reaction involving unicast neighbor discovery * message destined to the proxied address, pass it to * input function. */ return 1; default: break; } } /* * The proxying router can't forward traffic sent to a link-local * address, so signal the sender and discard the packet. This * behavior is clarified by the MIPv6 specification. */ if (ipv6_addr_type(&hdr->daddr) & IPV6_ADDR_LINKLOCAL) { dst_link_failure(skb); return -1; } return 0; } static inline int ip6_forward_finish(struct sk_buff *skb) { return dst_output(skb); } int ip6_forward(struct sk_buff *skb) { struct dst_entry *dst = skb->dst; struct ipv6hdr *hdr = ipv6_hdr(skb); struct inet6_skb_parm *opt = IP6CB(skb); if (ipv6_devconf.forwarding == 0) goto error; if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) { IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS); goto drop; } skb_forward_csum(skb); /* * We DO NOT make any processing on * RA packets, pushing them to user level AS IS * without ane WARRANTY that application will be able * to interpret them. The reason is that we * cannot make anything clever here. * * We are not end-node, so that if packet contains * AH/ESP, we cannot make anything. * Defragmentation also would be mistake, RA packets * cannot be fragmented, because there is no warranty * that different fragments will go along one path. --ANK */ if (opt->ra) { u8 *ptr = skb_network_header(skb) + opt->ra; if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3])) return 0; } /* * check and decrement ttl */ if (hdr->hop_limit <= 1) { /* Force OUTPUT device used as source address */ skb->dev = dst->dev; icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0, skb->dev); IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS); kfree_skb(skb); return -ETIMEDOUT; } /* XXX: idev->cnf.proxy_ndp? */ if (ipv6_devconf.proxy_ndp && pneigh_lookup(&nd_tbl, &hdr->daddr, skb->dev, 0)) { int proxied = ip6_forward_proxy_check(skb); if (proxied > 0) return ip6_input(skb); else if (proxied < 0) { IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS); goto drop; } } if (!xfrm6_route_forward(skb)) { IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_INDISCARDS); goto drop; } dst = skb->dst; /* IPv6 specs say nothing about it, but it is clear that we cannot send redirects to source routed frames. We don't send redirects to frames decapsulated from IPsec. */ if (skb->dev == dst->dev && dst->neighbour && opt->srcrt == 0 && !skb->sp) { struct in6_addr *target = NULL; struct rt6_info *rt; struct neighbour *n = dst->neighbour; /* * incoming and outgoing devices are the same * send a redirect. */ rt = (struct rt6_info *) dst; if ((rt->rt6i_flags & RTF_GATEWAY)) target = (struct in6_addr*)&n->primary_key; else target = &hdr->daddr; /* Limit redirects both by destination (here) and by source (inside ndisc_send_redirect) */ if (xrlim_allow(dst, 1*HZ)) ndisc_send_redirect(skb, n, target); } else { int addrtype = ipv6_addr_type(&hdr->saddr); /* This check is security critical. */ if (addrtype & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LOOPBACK)) goto error; if (addrtype & IPV6_ADDR_LINKLOCAL) { icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_NOT_NEIGHBOUR, 0, skb->dev); goto error; } } if (skb->len > dst_mtu(dst)) { /* Again, force OUTPUT device used as source address */ skb->dev = dst->dev; icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, dst_mtu(dst), skb->dev); IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INTOOBIGERRORS); IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_FRAGFAILS); kfree_skb(skb); return -EMSGSIZE; } if (skb_cow(skb, dst->dev->hard_header_len)) { IP6_INC_STATS(ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS); goto drop; } hdr = ipv6_hdr(skb); /* Mangling hops number delayed to point after skb COW */ hdr->hop_limit--; IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS); return NF_HOOK(PF_INET6,NF_IP6_FORWARD, skb, skb->dev, dst->dev, ip6_forward_finish); error: IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS); drop: kfree_skb(skb); return -EINVAL; } static void ip6_copy_metadata(struct sk_buff *to, struct sk_buff *from) { to->pkt_type = from->pkt_type; to->priority = from->priority; to->protocol = from->protocol; dst_release(to->dst); to->dst = dst_clone(from->dst); to->dev = from->dev; to->mark = from->mark; #ifdef CONFIG_NET_SCHED to->tc_index = from->tc_index; #endif nf_copy(to, from); #if defined(CONFIG_NETFILTER_XT_TARGET_TRACE) || \ defined(CONFIG_NETFILTER_XT_TARGET_TRACE_MODULE) to->nf_trace = from->nf_trace; #endif skb_copy_secmark(to, from); } int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr) { u16 offset = sizeof(struct ipv6hdr); struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); unsigned int packet_len = skb->tail - skb->network_header; int found_rhdr = 0; *nexthdr = &ipv6_hdr(skb)->nexthdr; while (offset + 1 <= packet_len) { switch (**nexthdr) { case NEXTHDR_HOP: break; case NEXTHDR_ROUTING: found_rhdr = 1; break; case NEXTHDR_DEST: #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE) if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) break; #endif if (found_rhdr) return offset; break; default : return offset; } offset += ipv6_optlen(exthdr); *nexthdr = &exthdr->nexthdr; exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) + offset); } return offset; } EXPORT_SYMBOL_GPL(ip6_find_1stfragopt); static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) { struct net_device *dev; struct sk_buff *frag; struct rt6_info *rt = (struct rt6_info*)skb->dst; struct ipv6_pinfo *np = skb->sk ? inet6_sk(skb->sk) : NULL; struct ipv6hdr *tmp_hdr; struct frag_hdr *fh; unsigned int mtu, hlen, left, len; __be32 frag_id = 0; int ptr, offset = 0, err=0; u8 *prevhdr, nexthdr = 0; dev = rt->u.dst.dev; hlen = ip6_find_1stfragopt(skb, &prevhdr); nexthdr = *prevhdr; mtu = ip6_skb_dst_mtu(skb); /* We must not fragment if the socket is set to force MTU discovery * or if the skb it not generated by a local socket. (This last * check should be redundant, but it's free.) */ if (!np || np->pmtudisc >= IPV6_PMTUDISC_DO) { skb->dev = skb->dst->dev; icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev); IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS); kfree_skb(skb); return -EMSGSIZE; } if (np && np->frag_size < mtu) { if (np->frag_size) mtu = np->frag_size; } mtu -= hlen + sizeof(struct frag_hdr); if (skb_shinfo(skb)->frag_list) { int first_len = skb_pagelen(skb); if (first_len - hlen > mtu || ((first_len - hlen) & 7) || skb_cloned(skb)) goto slow_path; for (frag = skb_shinfo(skb)->frag_list; frag; frag = frag->next) { /* Correct geometry. */ if (frag->len > mtu || ((frag->len & 7) && frag->next) || skb_headroom(frag) < hlen) goto slow_path; /* Partially cloned skb? */ if (skb_shared(frag)) goto slow_path; BUG_ON(frag->sk); if (skb->sk) { sock_hold(skb->sk); frag->sk = skb->sk; frag->destructor = sock_wfree; skb->truesize -= frag->truesize; } } err = 0; offset = 0; frag = skb_shinfo(skb)->frag_list; skb_shinfo(skb)->frag_list = NULL; /* BUILD HEADER */ *prevhdr = NEXTHDR_FRAGMENT; tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC); if (!tmp_hdr) { IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS); return -ENOMEM; } __skb_pull(skb, hlen); fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr)); __skb_push(skb, hlen); skb_reset_network_header(skb); memcpy(skb_network_header(skb), tmp_hdr, hlen); ipv6_select_ident(skb, fh); fh->nexthdr = nexthdr; fh->reserved = 0; fh->frag_off = htons(IP6_MF); frag_id = fh->identification; first_len = skb_pagelen(skb); skb->data_len = first_len - skb_headlen(skb); skb->len = first_len; ipv6_hdr(skb)->payload_len = htons(first_len - sizeof(struct ipv6hdr)); dst_hold(&rt->u.dst); for (;;) { /* Prepare header of the next frame, * before previous one went down. */ if (frag) { frag->ip_summed = CHECKSUM_NONE; skb_reset_transport_header(frag); fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr)); __skb_push(frag, hlen); skb_reset_network_header(frag); memcpy(skb_network_header(frag), tmp_hdr, hlen); offset += skb->len - hlen - sizeof(struct frag_hdr); fh->nexthdr = nexthdr; fh->reserved = 0; fh->frag_off = htons(offset); if (frag->next != NULL) fh->frag_off |= htons(IP6_MF); fh->identification = frag_id; ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); ip6_copy_metadata(frag, skb); } err = output(skb); if(!err) IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGCREATES); if (err || !frag) break; skb = frag; frag = skb->next; skb->next = NULL; } kfree(tmp_hdr); if (err == 0) { IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGOKS); dst_release(&rt->u.dst); return 0; } while (frag) { skb = frag->next; kfree_skb(frag); frag = skb; } IP6_INC_STATS(ip6_dst_idev(&rt->u.dst), IPSTATS_MIB_FRAGFAILS); dst_release(&rt->u.dst); return err; } slow_path: left = skb->len - hlen; /* Space per frame */ ptr = hlen; /* Where to start from */ /* * Fragment the datagram. */ *prevhdr = NEXTHDR_FRAGMENT; /* * Keep copying data until we run out. */ while(left > 0) { len = left; /* IF: it doesn't fit, use 'mtu' - the data space left */ if (len > mtu) len = mtu; /* IF: we are not sending upto and including the packet end then align the next start on an eight byte boundary */ if (len < left) { len &= ~7; } /* * Allocate buffer. */ if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) { NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n"); IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS); err = -ENOMEM; goto fail; } /* * Set up data on packet */ ip6_copy_metadata(frag, skb); skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev)); skb_put(frag, len + hlen + sizeof(struct frag_hdr)); skb_reset_network_header(frag); fh = (struct frag_hdr *)(skb_network_header(frag) + hlen); frag->transport_header = (frag->network_header + hlen + sizeof(struct frag_hdr)); /* * Charge the memory for the fragment to any owner * it might possess */ if (skb->sk) skb_set_owner_w(frag, skb->sk); /* * Copy the packet header into the new buffer. */ skb_copy_from_linear_data(skb, skb_network_header(frag), hlen); /* * Build fragment header. */ fh->nexthdr = nexthdr; fh->reserved = 0; if (!frag_id) { ipv6_select_ident(skb, fh); frag_id = fh->identification; } else fh->identification = frag_id; /* * Copy a block of the IP datagram. */ if (skb_copy_bits(skb, ptr, skb_transport_header(frag), len)) BUG(); left -= len; fh->frag_off = htons(offset); if (left > 0) fh->frag_off |= htons(IP6_MF); ipv6_hdr(frag)->payload_len = htons(frag->len - sizeof(struct ipv6hdr)); ptr += len; offset += len; /* * Put this fragment into the sending queue. */ err = output(frag); if (err) goto fail; IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGCREATES); } IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGOKS); kfree_skb(skb); return err; fail: IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS); kfree_skb(skb); return err; } static inline int ip6_rt_check(struct rt6key *rt_key, struct in6_addr *fl_addr, struct in6_addr *addr_cache) { return ((rt_key->plen != 128 || !ipv6_addr_equal(fl_addr, &rt_key->addr)) && (addr_cache == NULL || !ipv6_addr_equal(fl_addr, addr_cache))); } static struct dst_entry *ip6_sk_dst_check(struct sock *sk, struct dst_entry *dst, struct flowi *fl) { struct ipv6_pinfo *np = inet6_sk(sk); struct rt6_info *rt = (struct rt6_info *)dst; if (!dst) goto out; /* Yes, checking route validity in not connected * case is not very simple. Take into account, * that we do not support routing by source, TOS, * and MSG_DONTROUTE --ANK (980726) * * 1. ip6_rt_check(): If route was host route, * check that cached destination is current. * If it is network route, we still may * check its validity using saved pointer * to the last used address: daddr_cache. * We do not want to save whole address now, * (because main consumer of this service * is tcp, which has not this problem), * so that the last trick works only on connected * sockets. * 2. oif also should be the same. */ if (ip6_rt_check(&rt->rt6i_dst, &fl->fl6_dst, np->daddr_cache) || #ifdef CONFIG_IPV6_SUBTREES ip6_rt_check(&rt->rt6i_src, &fl->fl6_src, np->saddr_cache) || #endif (fl->oif && fl->oif != dst->dev->ifindex)) { dst_release(dst); dst = NULL; } out: return dst; } static int ip6_dst_lookup_tail(struct sock *sk, struct dst_entry **dst, struct flowi *fl) { int err; if (*dst == NULL) *dst = ip6_route_output(sk, fl); if ((err = (*dst)->error)) goto out_err_release; if (ipv6_addr_any(&fl->fl6_src)) { err = ipv6_get_saddr(*dst, &fl->fl6_dst, &fl->fl6_src); if (err) goto out_err_release; } #ifdef CONFIG_IPV6_OPTIMISTIC_DAD /* * Here if the dst entry we've looked up * has a neighbour entry that is in the INCOMPLETE * state and the src address from the flow is * marked as OPTIMISTIC, we release the found * dst entry and replace it instead with the * dst entry of the nexthop router */ if (!((*dst)->neighbour->nud_state & NUD_VALID)) { struct inet6_ifaddr *ifp; struct flowi fl_gw; int redirect; ifp = ipv6_get_ifaddr(&fl->fl6_src, (*dst)->dev, 1); redirect = (ifp && ifp->flags & IFA_F_OPTIMISTIC); if (ifp) in6_ifa_put(ifp); if (redirect) { /* * We need to get the dst entry for the * default router instead */ dst_release(*dst); memcpy(&fl_gw, fl, sizeof(struct flowi)); memset(&fl_gw.fl6_dst, 0, sizeof(struct in6_addr)); *dst = ip6_route_output(sk, &fl_gw); if ((err = (*dst)->error)) goto out_err_release; } } #endif return 0; out_err_release: if (err == -ENETUNREACH) IP6_INC_STATS_BH(NULL, IPSTATS_MIB_OUTNOROUTES); dst_release(*dst); *dst = NULL; return err; } /** * ip6_dst_lookup - perform route lookup on flow * @sk: socket which provides route info * @dst: pointer to dst_entry * for result * @fl: flow to lookup * * This function performs a route lookup on the given flow. * * It returns zero on success, or a standard errno code on error. */ int ip6_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl) { *dst = NULL; return ip6_dst_lookup_tail(sk, dst, fl); } EXPORT_SYMBOL_GPL(ip6_dst_lookup); /** * ip6_sk_dst_lookup - perform socket cached route lookup on flow * @sk: socket which provides the dst cache and route info * @dst: pointer to dst_entry * for result * @fl: flow to lookup * * This function performs a route lookup on the given flow with the * possibility of using the cached route in the socket if it is valid. * It will take the socket dst lock when operating on the dst cache. * As a result, this function can only be used in process context. * * It returns zero on success, or a standard errno code on error. */ int ip6_sk_dst_lookup(struct sock *sk, struct dst_entry **dst, struct flowi *fl) { *dst = NULL; if (sk) { *dst = sk_dst_check(sk, inet6_sk(sk)->dst_cookie); *dst = ip6_sk_dst_check(sk, *dst, fl); } return ip6_dst_lookup_tail(sk, dst, fl); } EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup); static inline int ip6_ufo_append_data(struct sock *sk, int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb), void *from, int length, int hh_len, int fragheaderlen, int transhdrlen, int mtu,unsigned int flags) { struct sk_buff *skb; int err; /* There is support for UDP large send offload by network * device, so create one single skb packet containing complete * udp datagram */ if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) { skb = sock_alloc_send_skb(sk, hh_len + fragheaderlen + transhdrlen + 20, (flags & MSG_DONTWAIT), &err); if (skb == NULL) return -ENOMEM; /* reserve space for Hardware header */ skb_reserve(skb, hh_len); /* create space for UDP/IP header */ skb_put(skb,fragheaderlen + transhdrlen); /* initialize network header pointer */ skb_reset_network_header(skb); /* initialize protocol header pointer */ skb->transport_header = skb->network_header + fragheaderlen; skb->ip_summed = CHECKSUM_PARTIAL; skb->csum = 0; sk->sk_sndmsg_off = 0; } err = skb_append_datato_frags(sk,skb, getfrag, from, (length - transhdrlen)); if (!err) { struct frag_hdr fhdr; /* specify the length of each IP datagram fragment*/ skb_shinfo(skb)->gso_size = mtu - fragheaderlen - sizeof(struct frag_hdr); skb_shinfo(skb)->gso_type = SKB_GSO_UDP; ipv6_select_ident(skb, &fhdr); skb_shinfo(skb)->ip6_frag_id = fhdr.identification; __skb_queue_tail(&sk->sk_write_queue, skb); return 0; } /* There is not enough support do UPD LSO, * so follow normal path */ kfree_skb(skb); return err; } int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb), void *from, int length, int transhdrlen, int hlimit, int tclass, struct ipv6_txoptions *opt, struct flowi *fl, struct rt6_info *rt, unsigned int flags) { struct inet_sock *inet = inet_sk(sk); struct ipv6_pinfo *np = inet6_sk(sk); struct sk_buff *skb; unsigned int maxfraglen, fragheaderlen; int exthdrlen; int hh_len; int mtu; int copy; int err; int offset = 0; int csummode = CHECKSUM_NONE; if (flags&MSG_PROBE) return 0; if (skb_queue_empty(&sk->sk_write_queue)) { /* * setup for corking */ if (opt) { if (np->cork.opt == NULL) { np->cork.opt = kmalloc(opt->tot_len, sk->sk_allocation); if (unlikely(np->cork.opt == NULL)) return -ENOBUFS; } else if (np->cork.opt->tot_len < opt->tot_len) { printk(KERN_DEBUG "ip6_append_data: invalid option length\n"); return -EINVAL; } memcpy(np->cork.opt, opt, opt->tot_len); inet->cork.flags |= IPCORK_OPT; /* need source address above miyazawa*/ } dst_hold(&rt->u.dst); np->cork.rt = rt; inet->cork.fl = *fl; np->cork.hop_limit = hlimit; np->cork.tclass = tclass; mtu = np->pmtudisc == IPV6_PMTUDISC_PROBE ? rt->u.dst.dev->mtu : dst_mtu(rt->u.dst.path); if (np->frag_size < mtu) { if (np->frag_size) mtu = np->frag_size; } inet->cork.fragsize = mtu; if (dst_allfrag(rt->u.dst.path)) inet->cork.flags |= IPCORK_ALLFRAG; inet->cork.length = 0; sk->sk_sndmsg_page = NULL; sk->sk_sndmsg_off = 0; exthdrlen = rt->u.dst.header_len + (opt ? opt->opt_flen : 0) - rt->u.dst.nfheader_len; length += exthdrlen; transhdrlen += exthdrlen; } else { rt = np->cork.rt; fl = &inet->cork.fl; if (inet->cork.flags & IPCORK_OPT) opt = np->cork.opt; transhdrlen = 0; exthdrlen = 0; mtu = inet->cork.fragsize; } hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); fragheaderlen = sizeof(struct ipv6hdr) + rt->u.dst.nfheader_len + (opt ? opt->opt_nflen : 0); maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen - sizeof(struct frag_hdr); if (mtu <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) { if (inet->cork.length + length > sizeof(struct ipv6hdr) + IPV6_MAXPLEN - fragheaderlen) { ipv6_local_error(sk, EMSGSIZE, fl, mtu-exthdrlen); return -EMSGSIZE; } } /* * Let's try using as much space as possible. * Use MTU if total length of the message fits into the MTU. * Otherwise, we need to reserve fragment header and * fragment alignment (= 8-15 octects, in total). * * Note that we may need to "move" the data from the tail of * of the buffer to the new fragment when we split * the message. * * FIXME: It may be fragmented into multiple chunks * at once if non-fragmentable extension headers * are too large. * --yoshfuji */ inet->cork.length += length; if (((length > mtu) && (sk->sk_protocol == IPPROTO_UDP)) && (rt->u.dst.dev->features & NETIF_F_UFO)) { err = ip6_ufo_append_data(sk, getfrag, from, length, hh_len, fragheaderlen, transhdrlen, mtu, flags); if (err) goto error; return 0; } if ((skb = skb_peek_tail(&sk->sk_write_queue)) == NULL) goto alloc_new_skb; while (length > 0) { /* Check if the remaining data fits into current packet. */ copy = (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - skb->len; if (copy < length) copy = maxfraglen - skb->len; if (copy <= 0) { char *data; unsigned int datalen; unsigned int fraglen; unsigned int fraggap; unsigned int alloclen; struct sk_buff *skb_prev; alloc_new_skb: skb_prev = skb; /* There's no room in the current skb */ if (skb_prev) fraggap = skb_prev->len - maxfraglen; else fraggap = 0; /* * If remaining data exceeds the mtu, * we know we need more fragment(s). */ datalen = length + fraggap; if (datalen > (inet->cork.length <= mtu && !(inet->cork.flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen) datalen = maxfraglen - fragheaderlen; fraglen = datalen + fragheaderlen; if ((flags & MSG_MORE) && !(rt->u.dst.dev->features&NETIF_F_SG)) alloclen = mtu; else alloclen = datalen + fragheaderlen; /* * The last fragment gets additional space at tail. * Note: we overallocate on fragments with MSG_MODE * because we have no idea if we're the last one. */ if (datalen == length + fraggap) alloclen += rt->u.dst.trailer_len; /* * We just reserve space for fragment header. * Note: this may be overallocation if the message * (without MSG_MORE) fits into the MTU. */ alloclen += sizeof(struct frag_hdr); if (transhdrlen) { skb = sock_alloc_send_skb(sk, alloclen + hh_len, (flags & MSG_DONTWAIT), &err); } else { skb = NULL; if (atomic_read(&sk->sk_wmem_alloc) <= 2 * sk->sk_sndbuf) skb = sock_wmalloc(sk, alloclen + hh_len, 1, sk->sk_allocation); if (unlikely(skb == NULL)) err = -ENOBUFS; } if (skb == NULL) goto error; /* * Fill in the control structures */ skb->ip_summed = csummode; skb->csum = 0; /* reserve for fragmentation */ skb_reserve(skb, hh_len+sizeof(struct frag_hdr)); /* * Find where to start putting bytes */ data = skb_put(skb, fraglen); skb_set_network_header(skb, exthdrlen); data += fragheaderlen; skb->transport_header = (skb->network_header + fragheaderlen); if (fraggap) { skb->csum = skb_copy_and_csum_bits( skb_prev, maxfraglen, data + transhdrlen, fraggap, 0); skb_prev->csum = csum_sub(skb_prev->csum, skb->csum); data += fraggap; pskb_trim_unique(skb_prev, maxfraglen); } copy = datalen - transhdrlen - fraggap; if (copy < 0) { err = -EINVAL; kfree_skb(skb); goto error; } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) { err = -EFAULT; kfree_skb(skb); goto error; } offset += copy; length -= datalen - fraggap; transhdrlen = 0; exthdrlen = 0; csummode = CHECKSUM_NONE; /* * Put the packet on the pending queue */ __skb_queue_tail(&sk->sk_write_queue, skb); continue; } if (copy > length) copy = length; if (!(rt->u.dst.dev->features&NETIF_F_SG)) { unsigned int off; off = skb->len; if (getfrag(from, skb_put(skb, copy), offset, copy, off, skb) < 0) { __skb_trim(skb, off); err = -EFAULT; goto error; } } else { int i = skb_shinfo(skb)->nr_frags; skb_frag_t *frag = &skb_shinfo(skb)->frags[i-1]; struct page *page = sk->sk_sndmsg_page; int off = sk->sk_sndmsg_off; unsigned int left; if (page && (left = PAGE_SIZE - off) > 0) { if (copy >= left) copy = left; if (page != frag->page) { if (i == MAX_SKB_FRAGS) { err = -EMSGSIZE; goto error; } get_page(page); skb_fill_page_desc(skb, i, page, sk->sk_sndmsg_off, 0); frag = &skb_shinfo(skb)->frags[i]; } } else if(i < MAX_SKB_FRAGS) { if (copy > PAGE_SIZE) copy = PAGE_SIZE; page = alloc_pages(sk->sk_allocation, 0); if (page == NULL) { err = -ENOMEM; goto error; } sk->sk_sndmsg_page = page; sk->sk_sndmsg_off = 0; skb_fill_page_desc(skb, i, page, 0, 0); frag = &skb_shinfo(skb)->frags[i]; } else { err = -EMSGSIZE; goto error; } if (getfrag(from, page_address(frag->page)+frag->page_offset+frag->size, offset, copy, skb->len, skb) < 0) { err = -EFAULT; goto error; } sk->sk_sndmsg_off += copy; frag->size += copy; skb->len += copy; skb->data_len += copy; skb->truesize += copy; atomic_add(copy, &sk->sk_wmem_alloc); } offset += copy; length -= copy; } return 0; error: inet->cork.length -= length; IP6_INC_STATS(rt->rt6i_idev, IPSTATS_MIB_OUTDISCARDS); return err; } static void ip6_cork_release(struct inet_sock *inet, struct ipv6_pinfo *np) { inet->cork.flags &= ~IPCORK_OPT; kfree(np->cork.opt); np->cork.opt = NULL; if (np->cork.rt) { dst_release(&np->cork.rt->u.dst); np->cork.rt = NULL; inet->cork.flags &= ~IPCORK_ALLFRAG; } memset(&inet->cork.fl, 0, sizeof(inet->cork.fl)); } int ip6_push_pending_frames(struct sock *sk) { struct sk_buff *skb, *tmp_skb; struct sk_buff **tail_skb; struct in6_addr final_dst_buf, *final_dst = &final_dst_buf; struct inet_sock *inet = inet_sk(sk); struct ipv6_pinfo *np = inet6_sk(sk); struct ipv6hdr *hdr; struct ipv6_txoptions *opt = np->cork.opt; struct rt6_info *rt = np->cork.rt; struct flowi *fl = &inet->cork.fl; unsigned char proto = fl->proto; int err = 0; if ((skb = __skb_dequeue(&sk->sk_write_queue)) == NULL) goto out; tail_skb = &(skb_shinfo(skb)->frag_list); /* move skb->data to ip header from ext header */ if (skb->data < skb_network_header(skb)) __skb_pull(skb, skb_network_offset(skb)); while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) { __skb_pull(tmp_skb, skb_network_header_len(skb)); *tail_skb = tmp_skb; tail_skb = &(tmp_skb->next); skb->len += tmp_skb->len; skb->data_len += tmp_skb->len; skb->truesize += tmp_skb->truesize; __sock_put(tmp_skb->sk); tmp_skb->destructor = NULL; tmp_skb->sk = NULL; } ipv6_addr_copy(final_dst, &fl->fl6_dst); __skb_pull(skb, skb_network_header_len(skb)); if (opt && opt->opt_flen) ipv6_push_frag_opts(skb, opt, &proto); if (opt && opt->opt_nflen) ipv6_push_nfrag_opts(skb, opt, &proto, &final_dst); skb_push(skb, sizeof(struct ipv6hdr)); skb_reset_network_header(skb); hdr = ipv6_hdr(skb); *(__be32*)hdr = fl->fl6_flowlabel | htonl(0x60000000 | ((int)np->cork.tclass << 20)); if (skb->len <= sizeof(struct ipv6hdr) + IPV6_MAXPLEN) hdr->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); else hdr->payload_len = 0; hdr->hop_limit = np->cork.hop_limit; hdr->nexthdr = proto; ipv6_addr_copy(&hdr->saddr, &fl->fl6_src); ipv6_addr_copy(&hdr->daddr, final_dst); skb->priority = sk->sk_priority; skb->dst = dst_clone(&rt->u.dst); IP6_INC_STATS(rt->rt6i_idev, IPSTATS_MIB_OUTREQUESTS); if (proto == IPPROTO_ICMPV6) { struct inet6_dev *idev = ip6_dst_idev(skb->dst); ICMP6MSGOUT_INC_STATS_BH(idev, icmp6_hdr(skb)->icmp6_type); ICMP6_INC_STATS_BH(idev, ICMP6_MIB_OUTMSGS); } err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dst->dev, dst_output); if (err) { if (err > 0) err = np->recverr ? net_xmit_errno(err) : 0; if (err) goto error; } out: ip6_cork_release(inet, np); return err; error: goto out; } void ip6_flush_pending_frames(struct sock *sk) { struct sk_buff *skb; while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) { if (skb->dst) IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_OUTDISCARDS); kfree_skb(skb); } ip6_cork_release(inet_sk(sk), inet6_sk(sk)); }