From 049bb96ff01980d257564260cf15c74396d9a5c3 Mon Sep 17 00:00:00 2001 From: Bart De Schuymer Date: Mon, 21 Oct 2002 17:28:24 +0000 Subject: *** empty log message *** --- br-nf-bds/linux2.5/net/ipv4/ip_output.c | 1042 +++++++++++++++++++++++++++++++ 1 file changed, 1042 insertions(+) create mode 100644 br-nf-bds/linux2.5/net/ipv4/ip_output.c (limited to 'br-nf-bds') diff --git a/br-nf-bds/linux2.5/net/ipv4/ip_output.c b/br-nf-bds/linux2.5/net/ipv4/ip_output.c new file mode 100644 index 0000000..c103c48 --- /dev/null +++ b/br-nf-bds/linux2.5/net/ipv4/ip_output.c @@ -0,0 +1,1042 @@ +/* + * 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 Internet Protocol (IP) output module. + * + * Version: $Id: ip_output.c,v 1.6 2002/10/21 17:28:24 bdschuym Exp $ + * + * Authors: Ross Biro, + * Fred N. van Kempen, + * Donald Becker, + * Alan Cox, + * Richard Underwood + * Stefan Becker, + * Jorge Cwik, + * Arnt Gulbrandsen, + * + * See ip_input.c for original log + * + * Fixes: + * Alan Cox : Missing nonblock feature in ip_build_xmit. + * Mike Kilburn : htons() missing in ip_build_xmit. + * Bradford Johnson: Fix faulty handling of some frames when + * no route is found. + * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit + * (in case if packet not accepted by + * output firewall rules) + * Mike McLagan : Routing by source + * Alexey Kuznetsov: use new route cache + * Andi Kleen: Fix broken PMTU recovery and remove + * some redundant tests. + * Vitaly E. Lavrov : Transparent proxy revived after year coma. + * Andi Kleen : Replace ip_reply with ip_send_reply. + * Andi Kleen : Split fast and slow ip_build_xmit path + * for decreased register pressure on x86 + * and more readibility. + * Marc Boucher : When call_out_firewall returns FW_QUEUE, + * silently drop skb instead of failing with -EPERM. + * Detlev Wengorz : Copy protocol for fragments. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Shall we try to damage output packets if routing dev changes? + */ + +int sysctl_ip_dynaddr = 0; +int sysctl_ip_default_ttl = IPDEFTTL; + +/* Generate a checksum for an outgoing IP datagram. */ +__inline__ void ip_send_check(struct iphdr *iph) +{ + iph->check = 0; + iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); +} + +/* dev_loopback_xmit for use with netfilter. */ +static int ip_dev_loopback_xmit(struct sk_buff *newskb) +{ + newskb->mac.raw = newskb->data; + __skb_pull(newskb, newskb->nh.raw - newskb->data); + newskb->pkt_type = PACKET_LOOPBACK; + newskb->ip_summed = CHECKSUM_UNNECESSARY; + BUG_TRAP(newskb->dst); + +#ifdef CONFIG_NETFILTER_DEBUG + nf_debug_ip_loopback_xmit(newskb); +#endif + netif_rx(newskb); + return 0; +} + +/* Don't just hand NF_HOOK skb->dst->output, in case netfilter hook + changes route */ +static inline int +output_maybe_reroute(struct sk_buff *skb) +{ + return skb->dst->output(skb); +} + +/* + * Add an ip header to a skbuff and send it out. + */ +int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk, + u32 saddr, u32 daddr, struct ip_options *opt) +{ + struct inet_opt *inet = inet_sk(sk); + struct rtable *rt = (struct rtable *)skb->dst; + struct iphdr *iph; + + /* Build the IP header. */ + if (opt) + iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr) + opt->optlen); + else + iph=(struct iphdr *)skb_push(skb,sizeof(struct iphdr)); + + iph->version = 4; + iph->ihl = 5; + iph->tos = inet->tos; + if (ip_dont_fragment(sk, &rt->u.dst)) + iph->frag_off = htons(IP_DF); + else + iph->frag_off = 0; + iph->ttl = inet->ttl; + iph->daddr = rt->rt_dst; + iph->saddr = rt->rt_src; + iph->protocol = sk->protocol; + iph->tot_len = htons(skb->len); + ip_select_ident(iph, &rt->u.dst, sk); + skb->nh.iph = iph; + + if (opt && opt->optlen) { + iph->ihl += opt->optlen>>2; + ip_options_build(skb, opt, daddr, rt, 0); + } + ip_send_check(iph); + + /* Send it out. */ + return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, + output_maybe_reroute); +} + +static inline int ip_finish_output2(struct sk_buff *skb) +{ + struct dst_entry *dst = skb->dst; + struct hh_cache *hh = dst->hh; + +#ifdef CONFIG_NETFILTER_DEBUG + nf_debug_ip_finish_output2(skb); +#endif /*CONFIG_NETFILTER_DEBUG*/ + + if (hh) { + read_lock_bh(&hh->hh_lock); + memcpy(skb->data - 16, hh->hh_data, 16); + read_unlock_bh(&hh->hh_lock); + skb_push(skb, hh->hh_len); + return hh->hh_output(skb); + } else if (dst->neighbour) + return dst->neighbour->output(skb); + + if (net_ratelimit()) + printk(KERN_DEBUG "ip_finish_output2: No header cache and no neighbour!\n"); + kfree_skb(skb); + return -EINVAL; +} + +__inline__ int ip_finish_output(struct sk_buff *skb) +{ + struct net_device *dev = skb->dst->dev; + + skb->dev = dev; + skb->protocol = htons(ETH_P_IP); + + return NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev, + ip_finish_output2); +} + +int ip_mc_output(struct sk_buff *skb) +{ + struct sock *sk = skb->sk; + struct rtable *rt = (struct rtable*)skb->dst; + struct net_device *dev = rt->u.dst.dev; + + /* + * If the indicated interface is up and running, send the packet. + */ + IP_INC_STATS(IpOutRequests); +#ifdef CONFIG_IP_ROUTE_NAT + if (rt->rt_flags & RTCF_NAT) + ip_do_nat(skb); +#endif + + skb->dev = dev; + skb->protocol = htons(ETH_P_IP); + + /* + * Multicasts are looped back for other local users + */ + + if (rt->rt_flags&RTCF_MULTICAST) { + if ((!sk || inet_sk(sk)->mc_loop) +#ifdef CONFIG_IP_MROUTE + /* Small optimization: do not loopback not local frames, + which returned after forwarding; they will be dropped + by ip_mr_input in any case. + Note, that local frames are looped back to be delivered + to local recipients. + + This check is duplicated in ip_mr_input at the moment. + */ + && ((rt->rt_flags&RTCF_LOCAL) || !(IPCB(skb)->flags&IPSKB_FORWARDED)) +#endif + ) { + struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); + if (newskb) + NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, + newskb->dev, + ip_dev_loopback_xmit); + } + + /* Multicasts with ttl 0 must not go beyond the host */ + + if (skb->nh.iph->ttl == 0) { + kfree_skb(skb); + return 0; + } + } + + if (rt->rt_flags&RTCF_BROADCAST) { + struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC); + if (newskb) + NF_HOOK(PF_INET, NF_IP_POST_ROUTING, newskb, NULL, + newskb->dev, ip_dev_loopback_xmit); + } + + return ip_finish_output(skb); +} + +int ip_output(struct sk_buff *skb) +{ +#ifdef CONFIG_IP_ROUTE_NAT + struct rtable *rt = (struct rtable*)skb->dst; +#endif + + IP_INC_STATS(IpOutRequests); + +#ifdef CONFIG_IP_ROUTE_NAT + if (rt->rt_flags&RTCF_NAT) + ip_do_nat(skb); +#endif + + return ip_finish_output(skb); +} + +/* Queues a packet to be sent, and starts the transmitter if necessary. + * This routine also needs to put in the total length and compute the + * checksum. We use to do this in two stages, ip_build_header() then + * this, but that scheme created a mess when routes disappeared etc. + * So we do it all here, and the TCP send engine has been changed to + * match. (No more unroutable FIN disasters, etc. wheee...) This will + * most likely make other reliable transport layers above IP easier + * to implement under Linux. + */ +static inline int ip_queue_xmit2(struct sk_buff *skb) +{ + struct sock *sk = skb->sk; + struct rtable *rt = (struct rtable *)skb->dst; + struct net_device *dev; + struct iphdr *iph = skb->nh.iph; + + dev = rt->u.dst.dev; + + /* This can happen when the transport layer has segments queued + * with a cached route, and by the time we get here things are + * re-routed to a device with a different MTU than the original + * device. Sick, but we must cover it. + */ + if (skb_headroom(skb) < dev->hard_header_len && dev->hard_header) { + struct sk_buff *skb2; + + skb2 = skb_realloc_headroom(skb, (dev->hard_header_len + 15) & ~15); + kfree_skb(skb); + if (skb2 == NULL) + return -ENOMEM; + if (sk) + skb_set_owner_w(skb2, sk); + skb = skb2; + iph = skb->nh.iph; + } + + if (skb->len > rt->u.dst.pmtu) { + unsigned int hlen; + if (!(sk->route_caps&NETIF_F_TSO)) + goto fragment; + + /* Hack zone: all this must be done by TCP. */ + hlen = ((skb->h.raw - skb->data) + (skb->h.th->doff << 2)); + skb_shinfo(skb)->tso_size = rt->u.dst.pmtu - hlen; + skb_shinfo(skb)->tso_segs = + (skb->len - hlen + skb_shinfo(skb)->tso_size - 1)/ + skb_shinfo(skb)->tso_size - 1; + } + + ip_select_ident_more(iph, &rt->u.dst, sk, skb_shinfo(skb)->tso_segs); + + /* Add an IP checksum. */ + ip_send_check(iph); + + skb->priority = sk->priority; + return skb->dst->output(skb); + +fragment: + if (ip_dont_fragment(sk, &rt->u.dst)) { + /* Reject packet ONLY if TCP might fragment + * it itself, if were careful enough. + */ + NETDEBUG(printk(KERN_DEBUG "sending pkt_too_big (len[%u] pmtu[%u]) to self\n", + skb->len, rt->u.dst.pmtu)); + + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, + htonl(rt->u.dst.pmtu)); + kfree_skb(skb); + return -EMSGSIZE; + } + ip_select_ident(iph, &rt->u.dst, sk); + if (skb->ip_summed == CHECKSUM_HW && + (skb = skb_checksum_help(skb)) == NULL) + return -ENOMEM; + return ip_fragment(skb, skb->dst->output); +} + +int ip_queue_xmit(struct sk_buff *skb) +{ + struct sock *sk = skb->sk; + struct inet_opt *inet = inet_sk(sk); + struct ip_options *opt = inet->opt; + struct rtable *rt; + struct iphdr *iph; + + /* Skip all of this if the packet is already routed, + * f.e. by something like SCTP. + */ + rt = (struct rtable *) skb->dst; + if (rt != NULL) + goto packet_routed; + + /* Make sure we can route this packet. */ + rt = (struct rtable *)__sk_dst_check(sk, 0); + if (rt == NULL) { + u32 daddr; + + /* Use correct destination address if we have options. */ + daddr = inet->daddr; + if(opt && opt->srr) + daddr = opt->faddr; + + /* If this fails, retransmit mechanism of transport layer will + * keep trying until route appears or the connection times itself + * out. + */ + if (ip_route_output(&rt, daddr, inet->saddr, + RT_CONN_FLAGS(sk), + sk->bound_dev_if)) + goto no_route; + __sk_dst_set(sk, &rt->u.dst); + tcp_v4_setup_caps(sk, &rt->u.dst); + } + skb->dst = dst_clone(&rt->u.dst); + +packet_routed: + if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway) + goto no_route; + + /* OK, we know where to send it, allocate and build IP header. */ + iph = (struct iphdr *) skb_push(skb, sizeof(struct iphdr) + (opt ? opt->optlen : 0)); + *((__u16 *)iph) = htons((4 << 12) | (5 << 8) | (inet->tos & 0xff)); + iph->tot_len = htons(skb->len); + if (ip_dont_fragment(sk, &rt->u.dst)) + iph->frag_off = htons(IP_DF); + else + iph->frag_off = 0; + iph->ttl = inet->ttl; + iph->protocol = sk->protocol; + iph->saddr = rt->rt_src; + iph->daddr = rt->rt_dst; + skb->nh.iph = iph; + /* Transport layer set skb->h.foo itself. */ + + if(opt && opt->optlen) { + iph->ihl += opt->optlen >> 2; + ip_options_build(skb, opt, inet->daddr, rt, 0); + } + + return NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, + ip_queue_xmit2); + +no_route: + IP_INC_STATS(IpOutNoRoutes); + kfree_skb(skb); + return -EHOSTUNREACH; +} + +/* + * Build and send a packet, with as little as one copy + * + * Doesn't care much about ip options... option length can be + * different for fragment at 0 and other fragments. + * + * Note that the fragment at the highest offset is sent first, + * so the getfrag routine can fill in the TCP/UDP checksum header + * field in the last fragment it sends... actually it also helps + * the reassemblers, they can put most packets in at the head of + * the fragment queue, and they know the total size in advance. This + * last feature will measurably improve the Linux fragment handler one + * day. + * + * The callback has five args, an arbitrary pointer (copy of frag), + * the source IP address (may depend on the routing table), the + * destination address (char *), the offset to copy from, and the + * length to be copied. + */ + +static int ip_build_xmit_slow(struct sock *sk, + int getfrag (const void *, + char *, + unsigned int, + unsigned int), + const void *frag, + unsigned length, + struct ipcm_cookie *ipc, + struct rtable *rt, + int flags) +{ + struct inet_opt *inet = inet_sk(sk); + unsigned int fraglen, maxfraglen, fragheaderlen; + int err; + int offset, mf; + int mtu; + u16 id; + + int hh_len = (rt->u.dst.dev->hard_header_len + 15)&~15; + int nfrags=0; + struct ip_options *opt = ipc->opt; + int df = 0; + + mtu = rt->u.dst.pmtu; + if (ip_dont_fragment(sk, &rt->u.dst)) + df = htons(IP_DF); + + length -= sizeof(struct iphdr); + + if (opt) { + fragheaderlen = sizeof(struct iphdr) + opt->optlen; + maxfraglen = ((mtu-sizeof(struct iphdr)-opt->optlen) & ~7) + fragheaderlen; + } else { + fragheaderlen = sizeof(struct iphdr); + + /* + * Fragheaderlen is the size of 'overhead' on each buffer. Now work + * out the size of the frames to send. + */ + + maxfraglen = ((mtu-sizeof(struct iphdr)) & ~7) + fragheaderlen; + } + + if (length + fragheaderlen > 0xFFFF) { + ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); + return -EMSGSIZE; + } + + /* + * Start at the end of the frame by handling the remainder. + */ + + offset = length - (length % (maxfraglen - fragheaderlen)); + + /* + * Amount of memory to allocate for final fragment. + */ + + fraglen = length - offset + fragheaderlen; + + if (length-offset==0) { + fraglen = maxfraglen; + offset -= maxfraglen-fragheaderlen; + } + + /* + * The last fragment will not have MF (more fragments) set. + */ + + mf = 0; + + /* + * Don't fragment packets for path mtu discovery. + */ + + if (offset > 0 && inet->pmtudisc == IP_PMTUDISC_DO) { + ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, mtu); + return -EMSGSIZE; + } + if (flags&MSG_PROBE) + goto out; + + /* + * Begin outputting the bytes. + */ + + id = inet->id++; + + do { + char *data; + struct sk_buff * skb; + + /* + * Get the memory we require with some space left for alignment. + */ + if (!(flags & MSG_DONTWAIT) || nfrags == 0) { + skb = sock_alloc_send_skb(sk, fraglen + hh_len + 15, + (flags & MSG_DONTWAIT), &err); + } else { + /* On a non-blocking write, we check for send buffer + * usage on the first fragment only. + */ + skb = sock_wmalloc(sk, fraglen + hh_len + 15, 1, + sk->allocation); + if (!skb) + err = -ENOBUFS; + } + if (skb == NULL) + goto error; + + /* + * Fill in the control structures + */ + + skb->priority = sk->priority; + skb->dst = dst_clone(&rt->u.dst); + skb_reserve(skb, hh_len); + + /* + * Find where to start putting bytes. + */ + + data = skb_put(skb, fraglen); + skb->nh.iph = (struct iphdr *)data; + + /* + * Only write IP header onto non-raw packets + */ + + { + struct iphdr *iph = (struct iphdr *)data; + + iph->version = 4; + iph->ihl = 5; + if (opt) { + iph->ihl += opt->optlen>>2; + ip_options_build(skb, opt, + ipc->addr, rt, offset); + } + iph->tos = inet->tos; + iph->tot_len = htons(fraglen - fragheaderlen + iph->ihl*4); + iph->frag_off = htons(offset>>3)|mf|df; + iph->id = id; + if (!mf) { + if (offset || !df) { + /* Select an unpredictable ident only + * for packets without DF or having + * been fragmented. + */ + __ip_select_ident(iph, &rt->u.dst, 0); + id = iph->id; + } + + /* + * Any further fragments will have MF set. + */ + mf = htons(IP_MF); + } + if (rt->rt_type == RTN_MULTICAST) + iph->ttl = inet->mc_ttl; + else + iph->ttl = inet->ttl; + iph->protocol = sk->protocol; + iph->check = 0; + iph->saddr = rt->rt_src; + iph->daddr = rt->rt_dst; + iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); + data += iph->ihl*4; + } + + /* + * User data callback + */ + + if (getfrag(frag, data, offset, fraglen-fragheaderlen)) { + err = -EFAULT; + kfree_skb(skb); + goto error; + } + + offset -= (maxfraglen-fragheaderlen); + fraglen = maxfraglen; + + nfrags++; + + err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, + skb->dst->dev, output_maybe_reroute); + if (err) { + if (err > 0) + err = inet->recverr ? net_xmit_errno(err) : 0; + if (err) + goto error; + } + } while (offset >= 0); + + if (nfrags>1) + ip_statistics[smp_processor_id()*2 + !in_softirq()].IpFragCreates += nfrags; +out: + return 0; + +error: + IP_INC_STATS(IpOutDiscards); + if (nfrags>1) + ip_statistics[smp_processor_id()*2 + !in_softirq()].IpFragCreates += nfrags; + return err; +} + +/* + * Fast path for unfragmented packets. + */ +int ip_build_xmit(struct sock *sk, + int getfrag (const void *, + char *, + unsigned int, + unsigned int), + const void *frag, + unsigned length, + struct ipcm_cookie *ipc, + struct rtable *rt, + int flags) +{ + struct inet_opt *inet = inet_sk(sk); + int err; + struct sk_buff *skb; + int df; + struct iphdr *iph; + + /* + * Try the simple case first. This leaves fragmented frames, and by + * choice RAW frames within 20 bytes of maximum size(rare) to the long path + */ + + if (!inet->hdrincl) { + length += sizeof(struct iphdr); + + /* + * Check for slow path. + */ + if (length > rt->u.dst.pmtu || ipc->opt != NULL) + return ip_build_xmit_slow(sk,getfrag,frag,length,ipc,rt,flags); + } else { + if (length > rt->u.dst.dev->mtu) { + ip_local_error(sk, EMSGSIZE, rt->rt_dst, inet->dport, + rt->u.dst.dev->mtu); + return -EMSGSIZE; + } + } + if (flags&MSG_PROBE) + goto out; + + /* + * Do path mtu discovery if needed. + */ + df = 0; + if (ip_dont_fragment(sk, &rt->u.dst)) + df = htons(IP_DF); + + /* + * Fast path for unfragmented frames without options. + */ + { + int hh_len = (rt->u.dst.dev->hard_header_len + 15)&~15; + + skb = sock_alloc_send_skb(sk, length+hh_len+15, + flags&MSG_DONTWAIT, &err); + if(skb==NULL) + goto error; + skb_reserve(skb, hh_len); + } + + skb->priority = sk->priority; + skb->dst = dst_clone(&rt->u.dst); + + skb->nh.iph = iph = (struct iphdr *)skb_put(skb, length); + + if (!inet->hdrincl) { + iph->version=4; + iph->ihl=5; + iph->tos = inet->tos; + iph->tot_len = htons(length); + iph->frag_off = df; + iph->ttl = inet->mc_ttl; + ip_select_ident(iph, &rt->u.dst, sk); + if (rt->rt_type != RTN_MULTICAST) + iph->ttl = inet->ttl; + iph->protocol=sk->protocol; + iph->saddr=rt->rt_src; + iph->daddr=rt->rt_dst; + iph->check=0; + iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); + err = getfrag(frag, ((char *)iph)+iph->ihl*4,0, length-iph->ihl*4); + } + else + err = getfrag(frag, (void *)iph, 0, length); + + if (err) + goto error_fault; + + err = NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, skb, NULL, rt->u.dst.dev, + output_maybe_reroute); + if (err > 0) + err = inet->recverr ? net_xmit_errno(err) : 0; + if (err) + goto error; +out: + return 0; + +error_fault: + err = -EFAULT; + kfree_skb(skb); +error: + IP_INC_STATS(IpOutDiscards); + return err; +} + +/* + * This IP datagram is too large to be sent in one piece. Break it up into + * smaller pieces (each of size equal to IP header plus + * a block of the data of the original IP data part) that will yet fit in a + * single device frame, and queue such a frame for sending. + * + * Yes this is inefficient, feel free to submit a quicker one. + */ + +int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*)) +{ + struct iphdr *iph; + int raw = 0; + int ptr; + struct net_device *dev; + struct sk_buff *skb2; + unsigned int mtu, hlen, left, len; + int offset; + int not_last_frag; + struct rtable *rt = (struct rtable*)skb->dst; + int err = 0; + + dev = rt->u.dst.dev; + + /* + * Point into the IP datagram header. + */ + + iph = skb->nh.iph; + + /* + * Setup starting values. + */ + + hlen = iph->ihl * 4; + left = skb->len - hlen; /* Space per frame */ + mtu = rt->u.dst.pmtu - hlen; /* Size of data space */ + ptr = raw + hlen; /* Where to start from */ + + /* + * Fragment the datagram. + */ + + offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3; + not_last_frag = iph->frag_off & htons(IP_MF); + + /* + * 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 ((skb2 = alloc_skb(len+hlen+dev->hard_header_len+15,GFP_ATOMIC)) == NULL) { + NETDEBUG(printk(KERN_INFO "IP: frag: no memory for new fragment!\n")); + err = -ENOMEM; + goto fail; + } + + /* + * Set up data on packet + */ + + skb2->pkt_type = skb->pkt_type; + skb2->priority = skb->priority; + skb_reserve(skb2, (dev->hard_header_len+15)&~15); + skb_put(skb2, len + hlen); + skb2->nh.raw = skb2->data; + skb2->h.raw = skb2->data + hlen; + skb2->protocol = skb->protocol; + skb2->security = skb->security; + + /* + * Charge the memory for the fragment to any owner + * it might possess + */ + + if (skb->sk) + skb_set_owner_w(skb2, skb->sk); + skb2->dst = dst_clone(skb->dst); + skb2->dev = skb->dev; + + /* + * Copy the packet header into the new buffer. + */ + + memcpy(skb2->nh.raw, skb->data, hlen); + + /* + * Copy a block of the IP datagram. + */ + if (skb_copy_bits(skb, ptr, skb2->h.raw, len)) + BUG(); + left -= len; + + /* + * Fill in the new header fields. + */ + iph = skb2->nh.iph; + iph->frag_off = htons((offset >> 3)); + + /* ANK: dirty, but effective trick. Upgrade options only if + * the segment to be fragmented was THE FIRST (otherwise, + * options are already fixed) and make it ONCE + * on the initial skb, so that all the following fragments + * will inherit fixed options. + */ + if (offset == 0) + ip_options_fragment(skb); + + /* Copy the flags to each fragment. */ + IPCB(skb2)->flags = IPCB(skb)->flags; + + /* + * Added AC : If we are fragmenting a fragment that's not the + * last fragment then keep MF on each bit + */ + if (left > 0 || not_last_frag) + iph->frag_off |= htons(IP_MF); + ptr += len; + offset += len; + +#ifdef CONFIG_NET_SCHED + skb2->tc_index = skb->tc_index; +#endif +#ifdef CONFIG_NETFILTER + skb2->nfmark = skb->nfmark; + /* Connection association is same as pre-frag packet */ + skb2->nfct = skb->nfct; + nf_conntrack_get(skb2->nfct); + skb2->nf_bridge = skb->nf_bridge; + nf_bridge_get(skb2->nf_bridge); +#ifdef CONFIG_NETFILTER_DEBUG + skb2->nf_debug = skb->nf_debug; +#endif +#endif + + /* + * Put this fragment into the sending queue. + */ + + IP_INC_STATS(IpFragCreates); + + iph->tot_len = htons(len + hlen); + + ip_send_check(iph); + + err = output(skb2); + if (err) + goto fail; + } + kfree_skb(skb); + IP_INC_STATS(IpFragOKs); + return err; + +fail: + kfree_skb(skb); + IP_INC_STATS(IpFragFails); + return err; +} + +/* + * Fetch data from kernel space and fill in checksum if needed. + */ +static int ip_reply_glue_bits(const void *dptr, char *to, unsigned int offset, + unsigned int fraglen) +{ + struct ip_reply_arg *dp = (struct ip_reply_arg*)dptr; + u16 *pktp = (u16 *)to; + struct iovec *iov; + int len; + int hdrflag = 1; + + iov = &dp->iov[0]; + if (offset >= iov->iov_len) { + offset -= iov->iov_len; + iov++; + hdrflag = 0; + } + len = iov->iov_len - offset; + if (fraglen > len) { /* overlapping. */ + dp->csum = csum_partial_copy_nocheck(iov->iov_base+offset, to, len, + dp->csum); + offset = 0; + fraglen -= len; + to += len; + iov++; + } + + dp->csum = csum_partial_copy_nocheck(iov->iov_base+offset, to, fraglen, + dp->csum); + + if (hdrflag && dp->csumoffset) + *(pktp + dp->csumoffset) = csum_fold(dp->csum); /* fill in checksum */ + return 0; +} + +/* + * Generic function to send a packet as reply to another packet. + * Used to send TCP resets so far. ICMP should use this function too. + * + * Should run single threaded per socket because it uses the sock + * structure to pass arguments. + */ +void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *arg, + unsigned int len) +{ + struct inet_opt *inet = inet_sk(sk); + struct { + struct ip_options opt; + char data[40]; + } replyopts; + struct ipcm_cookie ipc; + u32 daddr; + struct rtable *rt = (struct rtable*)skb->dst; + + if (ip_options_echo(&replyopts.opt, skb)) + return; + + daddr = ipc.addr = rt->rt_src; + ipc.opt = NULL; + + if (replyopts.opt.optlen) { + ipc.opt = &replyopts.opt; + + if (ipc.opt->srr) + daddr = replyopts.opt.faddr; + } + + if (ip_route_output(&rt, daddr, rt->rt_spec_dst, RT_TOS(skb->nh.iph->tos), 0)) + return; + + /* And let IP do all the hard work. + + This chunk is not reenterable, hence spinlock. + Note that it uses the fact, that this function is called + with locally disabled BH and that sk cannot be already spinlocked. + */ + bh_lock_sock(sk); + inet->tos = skb->nh.iph->tos; + sk->priority = skb->priority; + sk->protocol = skb->nh.iph->protocol; + ip_build_xmit(sk, ip_reply_glue_bits, arg, len, &ipc, rt, MSG_DONTWAIT); + bh_unlock_sock(sk); + + ip_rt_put(rt); +} + +/* + * IP protocol layer initialiser + */ + +static struct packet_type ip_packet_type = +{ + __constant_htons(ETH_P_IP), + NULL, /* All devices */ + ip_rcv, + (void*)1, + NULL, +}; + +/* + * IP registers the packet type and then calls the subprotocol initialisers + */ + +void __init ip_init(void) +{ + dev_add_pack(&ip_packet_type); + + ip_rt_init(); + inet_initpeers(); + +#ifdef CONFIG_IP_MULTICAST + proc_net_create("igmp", 0, ip_mc_procinfo); +#endif +} -- cgit v1.2.3