2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * The Internet Protocol (IP) output module.
8 * Version: $Id: ip_output.c,v 1.100 2002/02/01 22:01:03 davem Exp $
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Donald Becker, <becker@super.org>
13 * Alan Cox, <Alan.Cox@linux.org>
15 * Stefan Becker, <stefanb@yello.ping.de>
16 * Jorge Cwik, <jorge@laser.satlink.net>
17 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
18 * Hirokazu Takahashi, <taka@valinux.co.jp>
20 * See ip_input.c for original log
23 * Alan Cox : Missing nonblock feature in ip_build_xmit.
24 * Mike Kilburn : htons() missing in ip_build_xmit.
25 * Bradford Johnson: Fix faulty handling of some frames when
27 * Alexander Demenshin: Missing sk/skb free in ip_queue_xmit
28 * (in case if packet not accepted by
29 * output firewall rules)
30 * Mike McLagan : Routing by source
31 * Alexey Kuznetsov: use new route cache
32 * Andi Kleen: Fix broken PMTU recovery and remove
33 * some redundant tests.
34 * Vitaly E. Lavrov : Transparent proxy revived after year coma.
35 * Andi Kleen : Replace ip_reply with ip_send_reply.
36 * Andi Kleen : Split fast and slow ip_build_xmit path
37 * for decreased register pressure on x86
38 * and more readibility.
39 * Marc Boucher : When call_out_firewall returns FW_QUEUE,
40 * silently drop skb instead of failing with -EPERM.
41 * Detlev Wengorz : Copy protocol for fragments.
42 * Hirokazu Takahashi: HW checksumming for outgoing UDP
44 * Hirokazu Takahashi: sendfile() on UDP works now.
47 #include <asm/uaccess.h>
48 #include <asm/system.h>
49 #include <linux/module.h>
50 #include <linux/types.h>
51 #include <linux/kernel.h>
52 #include <linux/sched.h>
54 #include <linux/string.h>
55 #include <linux/errno.h>
56 #include <linux/config.h>
58 #include <linux/socket.h>
59 #include <linux/sockios.h>
61 #include <linux/inet.h>
62 #include <linux/netdevice.h>
63 #include <linux/etherdevice.h>
64 #include <linux/proc_fs.h>
65 #include <linux/stat.h>
66 #include <linux/init.h>
70 #include <net/protocol.h>
71 #include <net/route.h>
74 #include <linux/skbuff.h>
79 #include <net/checksum.h>
80 #include <net/inetpeer.h>
81 #include <net/checksum.h>
82 #include <linux/igmp.h>
83 #include <linux/netfilter_ipv4.h>
84 #include <linux/netfilter_bridge.h>
85 #include <linux/mroute.h>
86 #include <linux/netlink.h>
89 * Shall we try to damage output packets if routing dev changes?
92 int sysctl_ip_dynaddr
;
93 int sysctl_ip_default_ttl
= IPDEFTTL
;
95 /* Generate a checksum for an outgoing IP datagram. */
96 __inline__
void ip_send_check(struct iphdr
*iph
)
99 iph
->check
= ip_fast_csum((unsigned char *)iph
, iph
->ihl
);
102 /* dev_loopback_xmit for use with netfilter. */
103 static int ip_dev_loopback_xmit(struct sk_buff
*newskb
)
105 newskb
->mac
.raw
= newskb
->data
;
106 __skb_pull(newskb
, newskb
->nh
.raw
- newskb
->data
);
107 newskb
->pkt_type
= PACKET_LOOPBACK
;
108 newskb
->ip_summed
= CHECKSUM_UNNECESSARY
;
109 BUG_TRAP(newskb
->dst
);
115 static inline int ip_select_ttl(struct inet_sock
*inet
, struct dst_entry
*dst
)
117 int ttl
= inet
->uc_ttl
;
120 ttl
= dst_metric(dst
, RTAX_HOPLIMIT
);
125 * Add an ip header to a skbuff and send it out.
128 int ip_build_and_send_pkt(struct sk_buff
*skb
, struct sock
*sk
,
129 u32 saddr
, u32 daddr
, struct ip_options
*opt
)
131 struct inet_sock
*inet
= inet_sk(sk
);
132 struct rtable
*rt
= (struct rtable
*)skb
->dst
;
135 /* Build the IP header. */
137 iph
=(struct iphdr
*)skb_push(skb
,sizeof(struct iphdr
) + opt
->optlen
);
139 iph
=(struct iphdr
*)skb_push(skb
,sizeof(struct iphdr
));
143 iph
->tos
= inet
->tos
;
144 if (ip_dont_fragment(sk
, &rt
->u
.dst
))
145 iph
->frag_off
= htons(IP_DF
);
148 iph
->ttl
= ip_select_ttl(inet
, &rt
->u
.dst
);
149 iph
->daddr
= rt
->rt_dst
;
150 iph
->saddr
= rt
->rt_src
;
151 iph
->protocol
= sk
->sk_protocol
;
152 iph
->tot_len
= htons(skb
->len
);
153 ip_select_ident(iph
, &rt
->u
.dst
, sk
);
156 if (opt
&& opt
->optlen
) {
157 iph
->ihl
+= opt
->optlen
>>2;
158 ip_options_build(skb
, opt
, daddr
, rt
, 0);
162 skb
->priority
= sk
->sk_priority
;
165 return NF_HOOK(PF_INET
, NF_IP_LOCAL_OUT
, skb
, NULL
, rt
->u
.dst
.dev
,
169 static inline int ip_finish_output2(struct sk_buff
*skb
)
171 struct dst_entry
*dst
= skb
->dst
;
172 struct hh_cache
*hh
= dst
->hh
;
173 struct net_device
*dev
= dst
->dev
;
174 int hh_len
= LL_RESERVED_SPACE(dev
);
176 /* Be paranoid, rather than too clever. */
177 if (unlikely(skb_headroom(skb
) < hh_len
&& dev
->hard_header
)) {
178 struct sk_buff
*skb2
;
180 skb2
= skb_realloc_headroom(skb
, LL_RESERVED_SPACE(dev
));
186 skb_set_owner_w(skb2
, skb
->sk
);
191 #ifdef CONFIG_BRIDGE_NETFILTER
192 /* bridge-netfilter defers calling some IP hooks to the bridge layer
193 * and still needs the conntrack reference.
195 if (skb
->nf_bridge
== NULL
)
202 read_lock_bh(&hh
->hh_lock
);
203 hh_alen
= HH_DATA_ALIGN(hh
->hh_len
);
204 memcpy(skb
->data
- hh_alen
, hh
->hh_data
, hh_alen
);
205 read_unlock_bh(&hh
->hh_lock
);
206 skb_push(skb
, hh
->hh_len
);
207 return hh
->hh_output(skb
);
208 } else if (dst
->neighbour
)
209 return dst
->neighbour
->output(skb
);
212 printk(KERN_DEBUG
"ip_finish_output2: No header cache and no neighbour!\n");
217 int ip_finish_output(struct sk_buff
*skb
)
219 struct net_device
*dev
= skb
->dst
->dev
;
222 skb
->protocol
= htons(ETH_P_IP
);
224 return NF_HOOK(PF_INET
, NF_IP_POST_ROUTING
, skb
, NULL
, dev
,
228 int ip_mc_output(struct sk_buff
*skb
)
230 struct sock
*sk
= skb
->sk
;
231 struct rtable
*rt
= (struct rtable
*)skb
->dst
;
232 struct net_device
*dev
= rt
->u
.dst
.dev
;
235 * If the indicated interface is up and running, send the packet.
237 IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS
);
240 skb
->protocol
= htons(ETH_P_IP
);
243 * Multicasts are looped back for other local users
246 if (rt
->rt_flags
&RTCF_MULTICAST
) {
247 if ((!sk
|| inet_sk(sk
)->mc_loop
)
248 #ifdef CONFIG_IP_MROUTE
249 /* Small optimization: do not loopback not local frames,
250 which returned after forwarding; they will be dropped
251 by ip_mr_input in any case.
252 Note, that local frames are looped back to be delivered
255 This check is duplicated in ip_mr_input at the moment.
257 && ((rt
->rt_flags
&RTCF_LOCAL
) || !(IPCB(skb
)->flags
&IPSKB_FORWARDED
))
260 struct sk_buff
*newskb
= skb_clone(skb
, GFP_ATOMIC
);
262 NF_HOOK(PF_INET
, NF_IP_POST_ROUTING
, newskb
, NULL
,
264 ip_dev_loopback_xmit
);
267 /* Multicasts with ttl 0 must not go beyond the host */
269 if (skb
->nh
.iph
->ttl
== 0) {
275 if (rt
->rt_flags
&RTCF_BROADCAST
) {
276 struct sk_buff
*newskb
= skb_clone(skb
, GFP_ATOMIC
);
278 NF_HOOK(PF_INET
, NF_IP_POST_ROUTING
, newskb
, NULL
,
279 newskb
->dev
, ip_dev_loopback_xmit
);
282 if (skb
->len
> dst_mtu(&rt
->u
.dst
))
283 return ip_fragment(skb
, ip_finish_output
);
285 return ip_finish_output(skb
);
288 int ip_output(struct sk_buff
*skb
)
290 IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS
);
292 if (skb
->len
> dst_mtu(skb
->dst
) && !skb_shinfo(skb
)->tso_size
)
293 return ip_fragment(skb
, ip_finish_output
);
295 return ip_finish_output(skb
);
298 int ip_queue_xmit(struct sk_buff
*skb
, int ipfragok
)
300 struct sock
*sk
= skb
->sk
;
301 struct inet_sock
*inet
= inet_sk(sk
);
302 struct ip_options
*opt
= inet
->opt
;
306 /* Skip all of this if the packet is already routed,
307 * f.e. by something like SCTP.
309 rt
= (struct rtable
*) skb
->dst
;
313 /* Make sure we can route this packet. */
314 rt
= (struct rtable
*)__sk_dst_check(sk
, 0);
318 /* Use correct destination address if we have options. */
324 struct flowi fl
= { .oif
= sk
->sk_bound_dev_if
,
327 .saddr
= inet
->saddr
,
328 .tos
= RT_CONN_FLAGS(sk
) } },
329 .proto
= sk
->sk_protocol
,
331 { .sport
= inet
->sport
,
332 .dport
= inet
->dport
} } };
334 /* If this fails, retransmit mechanism of transport layer will
335 * keep trying until route appears or the connection times
338 if (ip_route_output_flow(&rt
, &fl
, sk
, 0))
341 __sk_dst_set(sk
, &rt
->u
.dst
);
342 tcp_v4_setup_caps(sk
, &rt
->u
.dst
);
344 skb
->dst
= dst_clone(&rt
->u
.dst
);
347 if (opt
&& opt
->is_strictroute
&& rt
->rt_dst
!= rt
->rt_gateway
)
350 /* OK, we know where to send it, allocate and build IP header. */
351 iph
= (struct iphdr
*) skb_push(skb
, sizeof(struct iphdr
) + (opt
? opt
->optlen
: 0));
352 *((__u16
*)iph
) = htons((4 << 12) | (5 << 8) | (inet
->tos
& 0xff));
353 iph
->tot_len
= htons(skb
->len
);
354 if (ip_dont_fragment(sk
, &rt
->u
.dst
) && !ipfragok
)
355 iph
->frag_off
= htons(IP_DF
);
358 iph
->ttl
= ip_select_ttl(inet
, &rt
->u
.dst
);
359 iph
->protocol
= sk
->sk_protocol
;
360 iph
->saddr
= rt
->rt_src
;
361 iph
->daddr
= rt
->rt_dst
;
363 /* Transport layer set skb->h.foo itself. */
365 if (opt
&& opt
->optlen
) {
366 iph
->ihl
+= opt
->optlen
>> 2;
367 ip_options_build(skb
, opt
, inet
->daddr
, rt
, 0);
370 ip_select_ident_more(iph
, &rt
->u
.dst
, sk
, skb_shinfo(skb
)->tso_segs
);
372 /* Add an IP checksum. */
375 skb
->priority
= sk
->sk_priority
;
377 return NF_HOOK(PF_INET
, NF_IP_LOCAL_OUT
, skb
, NULL
, rt
->u
.dst
.dev
,
381 IP_INC_STATS(IPSTATS_MIB_OUTNOROUTES
);
383 return -EHOSTUNREACH
;
387 static void ip_copy_metadata(struct sk_buff
*to
, struct sk_buff
*from
)
389 to
->pkt_type
= from
->pkt_type
;
390 to
->priority
= from
->priority
;
391 to
->protocol
= from
->protocol
;
392 dst_release(to
->dst
);
393 to
->dst
= dst_clone(from
->dst
);
396 /* Copy the flags to each fragment. */
397 IPCB(to
)->flags
= IPCB(from
)->flags
;
399 #ifdef CONFIG_NET_SCHED
400 to
->tc_index
= from
->tc_index
;
402 #ifdef CONFIG_NETFILTER
403 to
->nfmark
= from
->nfmark
;
404 to
->nfcache
= from
->nfcache
;
405 /* Connection association is same as pre-frag packet */
406 nf_conntrack_put(to
->nfct
);
407 to
->nfct
= from
->nfct
;
408 nf_conntrack_get(to
->nfct
);
409 to
->nfctinfo
= from
->nfctinfo
;
410 #ifdef CONFIG_BRIDGE_NETFILTER
411 nf_bridge_put(to
->nf_bridge
);
412 to
->nf_bridge
= from
->nf_bridge
;
413 nf_bridge_get(to
->nf_bridge
);
419 * This IP datagram is too large to be sent in one piece. Break it up into
420 * smaller pieces (each of size equal to IP header plus
421 * a block of the data of the original IP data part) that will yet fit in a
422 * single device frame, and queue such a frame for sending.
425 int ip_fragment(struct sk_buff
*skb
, int (*output
)(struct sk_buff
*))
430 struct net_device
*dev
;
431 struct sk_buff
*skb2
;
432 unsigned int mtu
, hlen
, left
, len
, ll_rs
;
435 struct rtable
*rt
= (struct rtable
*)skb
->dst
;
441 * Point into the IP datagram header.
446 if (unlikely((iph
->frag_off
& htons(IP_DF
)) && !skb
->local_df
)) {
447 icmp_send(skb
, ICMP_DEST_UNREACH
, ICMP_FRAG_NEEDED
,
448 htonl(dst_mtu(&rt
->u
.dst
)));
454 * Setup starting values.
458 mtu
= dst_mtu(&rt
->u
.dst
) - hlen
; /* Size of data space */
460 /* When frag_list is given, use it. First, check its validity:
461 * some transformers could create wrong frag_list or break existing
462 * one, it is not prohibited. In this case fall back to copying.
464 * LATER: this step can be merged to real generation of fragments,
465 * we can switch to copy when see the first bad fragment.
467 if (skb_shinfo(skb
)->frag_list
) {
468 struct sk_buff
*frag
;
469 int first_len
= skb_pagelen(skb
);
471 if (first_len
- hlen
> mtu
||
472 ((first_len
- hlen
) & 7) ||
473 (iph
->frag_off
& htons(IP_MF
|IP_OFFSET
)) ||
477 for (frag
= skb_shinfo(skb
)->frag_list
; frag
; frag
= frag
->next
) {
478 /* Correct geometry. */
479 if (frag
->len
> mtu
||
480 ((frag
->len
& 7) && frag
->next
) ||
481 skb_headroom(frag
) < hlen
)
484 /* Partially cloned skb? */
485 if (skb_shared(frag
))
492 frag
->destructor
= sock_wfree
;
493 skb
->truesize
-= frag
->truesize
;
497 /* Everything is OK. Generate! */
501 frag
= skb_shinfo(skb
)->frag_list
;
502 skb_shinfo(skb
)->frag_list
= NULL
;
503 skb
->data_len
= first_len
- skb_headlen(skb
);
504 skb
->len
= first_len
;
505 iph
->tot_len
= htons(first_len
);
506 iph
->frag_off
= htons(IP_MF
);
510 /* Prepare header of the next frame,
511 * before previous one went down. */
513 frag
->ip_summed
= CHECKSUM_NONE
;
514 frag
->h
.raw
= frag
->data
;
515 frag
->nh
.raw
= __skb_push(frag
, hlen
);
516 memcpy(frag
->nh
.raw
, iph
, hlen
);
518 iph
->tot_len
= htons(frag
->len
);
519 ip_copy_metadata(frag
, skb
);
521 ip_options_fragment(frag
);
522 offset
+= skb
->len
- hlen
;
523 iph
->frag_off
= htons(offset
>>3);
524 if (frag
->next
!= NULL
)
525 iph
->frag_off
|= htons(IP_MF
);
526 /* Ready, complete checksum */
541 IP_INC_STATS(IPSTATS_MIB_FRAGOKS
);
550 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS
);
555 left
= skb
->len
- hlen
; /* Space per frame */
556 ptr
= raw
+ hlen
; /* Where to start from */
558 #ifdef CONFIG_BRIDGE_NETFILTER
559 /* for bridged IP traffic encapsulated inside f.e. a vlan header,
560 * we need to make room for the encapsulating header */
561 ll_rs
= LL_RESERVED_SPACE_EXTRA(rt
->u
.dst
.dev
, nf_bridge_pad(skb
));
562 mtu
-= nf_bridge_pad(skb
);
564 ll_rs
= LL_RESERVED_SPACE(rt
->u
.dst
.dev
);
567 * Fragment the datagram.
570 offset
= (ntohs(iph
->frag_off
) & IP_OFFSET
) << 3;
571 not_last_frag
= iph
->frag_off
& htons(IP_MF
);
574 * Keep copying data until we run out.
579 /* IF: it doesn't fit, use 'mtu' - the data space left */
582 /* IF: we are not sending upto and including the packet end
583 then align the next start on an eight byte boundary */
591 if ((skb2
= alloc_skb(len
+hlen
+ll_rs
, GFP_ATOMIC
)) == NULL
) {
592 NETDEBUG(printk(KERN_INFO
"IP: frag: no memory for new fragment!\n"));
598 * Set up data on packet
601 ip_copy_metadata(skb2
, skb
);
602 skb_reserve(skb2
, ll_rs
);
603 skb_put(skb2
, len
+ hlen
);
604 skb2
->nh
.raw
= skb2
->data
;
605 skb2
->h
.raw
= skb2
->data
+ hlen
;
608 * Charge the memory for the fragment to any owner
613 skb_set_owner_w(skb2
, skb
->sk
);
616 * Copy the packet header into the new buffer.
619 memcpy(skb2
->nh
.raw
, skb
->data
, hlen
);
622 * Copy a block of the IP datagram.
624 if (skb_copy_bits(skb
, ptr
, skb2
->h
.raw
, len
))
629 * Fill in the new header fields.
632 iph
->frag_off
= htons((offset
>> 3));
634 /* ANK: dirty, but effective trick. Upgrade options only if
635 * the segment to be fragmented was THE FIRST (otherwise,
636 * options are already fixed) and make it ONCE
637 * on the initial skb, so that all the following fragments
638 * will inherit fixed options.
641 ip_options_fragment(skb
);
644 * Added AC : If we are fragmenting a fragment that's not the
645 * last fragment then keep MF on each bit
647 if (left
> 0 || not_last_frag
)
648 iph
->frag_off
|= htons(IP_MF
);
653 * Put this fragment into the sending queue.
656 IP_INC_STATS(IPSTATS_MIB_FRAGCREATES
);
658 iph
->tot_len
= htons(len
+ hlen
);
667 IP_INC_STATS(IPSTATS_MIB_FRAGOKS
);
672 IP_INC_STATS(IPSTATS_MIB_FRAGFAILS
);
677 ip_generic_getfrag(void *from
, char *to
, int offset
, int len
, int odd
, struct sk_buff
*skb
)
679 struct iovec
*iov
= from
;
681 if (skb
->ip_summed
== CHECKSUM_HW
) {
682 if (memcpy_fromiovecend(to
, iov
, offset
, len
) < 0)
685 unsigned int csum
= 0;
686 if (csum_partial_copy_fromiovecend(to
, iov
, offset
, len
, &csum
) < 0)
688 skb
->csum
= csum_block_add(skb
->csum
, csum
, odd
);
693 static inline unsigned int
694 csum_page(struct page
*page
, int offset
, int copy
)
699 csum
= csum_partial(kaddr
+ offset
, copy
, 0);
705 * ip_append_data() and ip_append_page() can make one large IP datagram
706 * from many pieces of data. Each pieces will be holded on the socket
707 * until ip_push_pending_frames() is called. Each piece can be a page
710 * Not only UDP, other transport protocols - e.g. raw sockets - can use
711 * this interface potentially.
713 * LATER: length must be adjusted by pad at tail, when it is required.
715 int ip_append_data(struct sock
*sk
,
716 int getfrag(void *from
, char *to
, int offset
, int len
,
717 int odd
, struct sk_buff
*skb
),
718 void *from
, int length
, int transhdrlen
,
719 struct ipcm_cookie
*ipc
, struct rtable
*rt
,
722 struct inet_sock
*inet
= inet_sk(sk
);
725 struct ip_options
*opt
= NULL
;
732 unsigned int maxfraglen
, fragheaderlen
;
733 int csummode
= CHECKSUM_NONE
;
738 if (skb_queue_empty(&sk
->sk_write_queue
)) {
744 if (inet
->cork
.opt
== NULL
) {
745 inet
->cork
.opt
= kmalloc(sizeof(struct ip_options
) + 40, sk
->sk_allocation
);
746 if (unlikely(inet
->cork
.opt
== NULL
))
749 memcpy(inet
->cork
.opt
, opt
, sizeof(struct ip_options
)+opt
->optlen
);
750 inet
->cork
.flags
|= IPCORK_OPT
;
751 inet
->cork
.addr
= ipc
->addr
;
753 dst_hold(&rt
->u
.dst
);
754 inet
->cork
.fragsize
= mtu
= dst_mtu(rt
->u
.dst
.path
);
756 inet
->cork
.length
= 0;
757 sk
->sk_sndmsg_page
= NULL
;
758 sk
->sk_sndmsg_off
= 0;
759 if ((exthdrlen
= rt
->u
.dst
.header_len
) != 0) {
761 transhdrlen
+= exthdrlen
;
765 if (inet
->cork
.flags
& IPCORK_OPT
)
766 opt
= inet
->cork
.opt
;
770 mtu
= inet
->cork
.fragsize
;
772 hh_len
= LL_RESERVED_SPACE(rt
->u
.dst
.dev
);
774 fragheaderlen
= sizeof(struct iphdr
) + (opt
? opt
->optlen
: 0);
775 maxfraglen
= ((mtu
- fragheaderlen
) & ~7) + fragheaderlen
;
777 if (inet
->cork
.length
+ length
> 0xFFFF - fragheaderlen
) {
778 ip_local_error(sk
, EMSGSIZE
, rt
->rt_dst
, inet
->dport
, mtu
-exthdrlen
);
783 * transhdrlen > 0 means that this is the first fragment and we wish
784 * it won't be fragmented in the future.
787 length
+ fragheaderlen
<= mtu
&&
788 rt
->u
.dst
.dev
->features
&(NETIF_F_IP_CSUM
|NETIF_F_NO_CSUM
|NETIF_F_HW_CSUM
) &&
790 csummode
= CHECKSUM_HW
;
792 inet
->cork
.length
+= length
;
794 /* So, what's going on in the loop below?
796 * We use calculated fragment length to generate chained skb,
797 * each of segments is IP fragment ready for sending to network after
798 * adding appropriate IP header.
801 if ((skb
= skb_peek_tail(&sk
->sk_write_queue
)) == NULL
)
805 /* Check if the remaining data fits into current packet. */
806 copy
= mtu
- skb
->len
;
808 copy
= maxfraglen
- skb
->len
;
811 unsigned int datalen
;
812 unsigned int fraglen
;
813 unsigned int fraggap
;
814 unsigned int alloclen
;
815 struct sk_buff
*skb_prev
;
819 fraggap
= skb_prev
->len
- maxfraglen
;
824 * If remaining data exceeds the mtu,
825 * we know we need more fragment(s).
827 datalen
= length
+ fraggap
;
828 if (datalen
> mtu
- fragheaderlen
)
829 datalen
= maxfraglen
- fragheaderlen
;
830 fraglen
= datalen
+ fragheaderlen
;
832 if ((flags
& MSG_MORE
) &&
833 !(rt
->u
.dst
.dev
->features
&NETIF_F_SG
))
836 alloclen
= datalen
+ fragheaderlen
;
838 /* The last fragment gets additional space at tail.
839 * Note, with MSG_MORE we overallocate on fragments,
840 * because we have no idea what fragment will be
843 if (datalen
== length
)
844 alloclen
+= rt
->u
.dst
.trailer_len
;
847 skb
= sock_alloc_send_skb(sk
,
848 alloclen
+ hh_len
+ 15,
849 (flags
& MSG_DONTWAIT
), &err
);
852 if (atomic_read(&sk
->sk_wmem_alloc
) <=
854 skb
= sock_wmalloc(sk
,
855 alloclen
+ hh_len
+ 15, 1,
857 if (unlikely(skb
== NULL
))
864 * Fill in the control structures
866 skb
->ip_summed
= csummode
;
868 skb_reserve(skb
, hh_len
);
871 * Find where to start putting bytes.
873 data
= skb_put(skb
, fraglen
);
874 skb
->nh
.raw
= data
+ exthdrlen
;
875 data
+= fragheaderlen
;
876 skb
->h
.raw
= data
+ exthdrlen
;
879 skb
->csum
= skb_copy_and_csum_bits(
880 skb_prev
, maxfraglen
,
881 data
+ transhdrlen
, fraggap
, 0);
882 skb_prev
->csum
= csum_sub(skb_prev
->csum
,
885 skb_trim(skb_prev
, maxfraglen
);
888 copy
= datalen
- transhdrlen
- fraggap
;
889 if (copy
> 0 && getfrag(from
, data
+ transhdrlen
, offset
, copy
, fraggap
, skb
) < 0) {
896 length
-= datalen
- fraggap
;
899 csummode
= CHECKSUM_NONE
;
902 * Put the packet on the pending queue.
904 __skb_queue_tail(&sk
->sk_write_queue
, skb
);
911 if (!(rt
->u
.dst
.dev
->features
&NETIF_F_SG
)) {
915 if (getfrag(from
, skb_put(skb
, copy
),
916 offset
, copy
, off
, skb
) < 0) {
917 __skb_trim(skb
, off
);
922 int i
= skb_shinfo(skb
)->nr_frags
;
923 skb_frag_t
*frag
= &skb_shinfo(skb
)->frags
[i
-1];
924 struct page
*page
= sk
->sk_sndmsg_page
;
925 int off
= sk
->sk_sndmsg_off
;
928 if (page
&& (left
= PAGE_SIZE
- off
) > 0) {
931 if (page
!= frag
->page
) {
932 if (i
== MAX_SKB_FRAGS
) {
937 skb_fill_page_desc(skb
, i
, page
, sk
->sk_sndmsg_off
, 0);
938 frag
= &skb_shinfo(skb
)->frags
[i
];
940 } else if (i
< MAX_SKB_FRAGS
) {
941 if (copy
> PAGE_SIZE
)
943 page
= alloc_pages(sk
->sk_allocation
, 0);
948 sk
->sk_sndmsg_page
= page
;
949 sk
->sk_sndmsg_off
= 0;
951 skb_fill_page_desc(skb
, i
, page
, 0, 0);
952 frag
= &skb_shinfo(skb
)->frags
[i
];
953 skb
->truesize
+= PAGE_SIZE
;
954 atomic_add(PAGE_SIZE
, &sk
->sk_wmem_alloc
);
959 if (getfrag(from
, page_address(frag
->page
)+frag
->page_offset
+frag
->size
, offset
, copy
, skb
->len
, skb
) < 0) {
963 sk
->sk_sndmsg_off
+= copy
;
966 skb
->data_len
+= copy
;
975 inet
->cork
.length
-= length
;
976 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS
);
980 ssize_t
ip_append_page(struct sock
*sk
, struct page
*page
,
981 int offset
, size_t size
, int flags
)
983 struct inet_sock
*inet
= inet_sk(sk
);
986 struct ip_options
*opt
= NULL
;
991 unsigned int maxfraglen
, fragheaderlen
, fraggap
;
999 if (skb_queue_empty(&sk
->sk_write_queue
))
1003 if (inet
->cork
.flags
& IPCORK_OPT
)
1004 opt
= inet
->cork
.opt
;
1006 if (!(rt
->u
.dst
.dev
->features
&NETIF_F_SG
))
1009 hh_len
= LL_RESERVED_SPACE(rt
->u
.dst
.dev
);
1010 mtu
= inet
->cork
.fragsize
;
1012 fragheaderlen
= sizeof(struct iphdr
) + (opt
? opt
->optlen
: 0);
1013 maxfraglen
= ((mtu
- fragheaderlen
) & ~7) + fragheaderlen
;
1015 if (inet
->cork
.length
+ size
> 0xFFFF - fragheaderlen
) {
1016 ip_local_error(sk
, EMSGSIZE
, rt
->rt_dst
, inet
->dport
, mtu
);
1020 if ((skb
= skb_peek_tail(&sk
->sk_write_queue
)) == NULL
)
1023 inet
->cork
.length
+= size
;
1028 /* Check if the remaining data fits into current packet. */
1029 len
= mtu
- skb
->len
;
1031 len
= maxfraglen
- skb
->len
;
1033 struct sk_buff
*skb_prev
;
1040 fraggap
= skb_prev
->len
- maxfraglen
;
1044 alloclen
= fragheaderlen
+ hh_len
+ fraggap
+ 15;
1045 skb
= sock_wmalloc(sk
, alloclen
, 1, sk
->sk_allocation
);
1046 if (unlikely(!skb
)) {
1052 * Fill in the control structures
1054 skb
->ip_summed
= CHECKSUM_NONE
;
1056 skb_reserve(skb
, hh_len
);
1059 * Find where to start putting bytes.
1061 data
= skb_put(skb
, fragheaderlen
+ fraggap
);
1062 skb
->nh
.iph
= iph
= (struct iphdr
*)data
;
1063 data
+= fragheaderlen
;
1067 skb
->csum
= skb_copy_and_csum_bits(
1068 skb_prev
, maxfraglen
,
1070 skb_prev
->csum
= csum_sub(skb_prev
->csum
,
1072 skb_trim(skb_prev
, maxfraglen
);
1076 * Put the packet on the pending queue.
1078 __skb_queue_tail(&sk
->sk_write_queue
, skb
);
1082 i
= skb_shinfo(skb
)->nr_frags
;
1085 if (skb_can_coalesce(skb
, i
, page
, offset
)) {
1086 skb_shinfo(skb
)->frags
[i
-1].size
+= len
;
1087 } else if (i
< MAX_SKB_FRAGS
) {
1089 skb_fill_page_desc(skb
, i
, page
, offset
, len
);
1095 if (skb
->ip_summed
== CHECKSUM_NONE
) {
1097 csum
= csum_page(page
, offset
, len
);
1098 skb
->csum
= csum_block_add(skb
->csum
, csum
, skb
->len
);
1102 skb
->data_len
+= len
;
1109 inet
->cork
.length
-= size
;
1110 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS
);
1115 * Combined all pending IP fragments on the socket as one IP datagram
1116 * and push them out.
1118 int ip_push_pending_frames(struct sock
*sk
)
1120 struct sk_buff
*skb
, *tmp_skb
;
1121 struct sk_buff
**tail_skb
;
1122 struct inet_sock
*inet
= inet_sk(sk
);
1123 struct ip_options
*opt
= NULL
;
1124 struct rtable
*rt
= inet
->cork
.rt
;
1130 if ((skb
= __skb_dequeue(&sk
->sk_write_queue
)) == NULL
)
1132 tail_skb
= &(skb_shinfo(skb
)->frag_list
);
1134 /* move skb->data to ip header from ext header */
1135 if (skb
->data
< skb
->nh
.raw
)
1136 __skb_pull(skb
, skb
->nh
.raw
- skb
->data
);
1137 while ((tmp_skb
= __skb_dequeue(&sk
->sk_write_queue
)) != NULL
) {
1138 __skb_pull(tmp_skb
, skb
->h
.raw
- skb
->nh
.raw
);
1139 *tail_skb
= tmp_skb
;
1140 tail_skb
= &(tmp_skb
->next
);
1141 skb
->len
+= tmp_skb
->len
;
1142 skb
->data_len
+= tmp_skb
->len
;
1143 skb
->truesize
+= tmp_skb
->truesize
;
1144 __sock_put(tmp_skb
->sk
);
1145 tmp_skb
->destructor
= NULL
;
1149 /* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow
1150 * to fragment the frame generated here. No matter, what transforms
1151 * how transforms change size of the packet, it will come out.
1153 if (inet
->pmtudisc
!= IP_PMTUDISC_DO
)
1156 /* DF bit is set when we want to see DF on outgoing frames.
1157 * If local_df is set too, we still allow to fragment this frame
1159 if (inet
->pmtudisc
== IP_PMTUDISC_DO
||
1160 (skb
->len
<= dst_mtu(&rt
->u
.dst
) &&
1161 ip_dont_fragment(sk
, &rt
->u
.dst
)))
1164 if (inet
->cork
.flags
& IPCORK_OPT
)
1165 opt
= inet
->cork
.opt
;
1167 if (rt
->rt_type
== RTN_MULTICAST
)
1170 ttl
= ip_select_ttl(inet
, &rt
->u
.dst
);
1172 iph
= (struct iphdr
*)skb
->data
;
1176 iph
->ihl
+= opt
->optlen
>>2;
1177 ip_options_build(skb
, opt
, inet
->cork
.addr
, rt
, 0);
1179 iph
->tos
= inet
->tos
;
1180 iph
->tot_len
= htons(skb
->len
);
1183 __ip_select_ident(iph
, &rt
->u
.dst
, 0);
1185 iph
->id
= htons(inet
->id
++);
1188 iph
->protocol
= sk
->sk_protocol
;
1189 iph
->saddr
= rt
->rt_src
;
1190 iph
->daddr
= rt
->rt_dst
;
1193 skb
->priority
= sk
->sk_priority
;
1194 skb
->dst
= dst_clone(&rt
->u
.dst
);
1196 /* Netfilter gets whole the not fragmented skb. */
1197 err
= NF_HOOK(PF_INET
, NF_IP_LOCAL_OUT
, skb
, NULL
,
1198 skb
->dst
->dev
, dst_output
);
1201 err
= inet
->recverr
? net_xmit_errno(err
) : 0;
1207 inet
->cork
.flags
&= ~IPCORK_OPT
;
1208 if (inet
->cork
.opt
) {
1209 kfree(inet
->cork
.opt
);
1210 inet
->cork
.opt
= NULL
;
1212 if (inet
->cork
.rt
) {
1213 ip_rt_put(inet
->cork
.rt
);
1214 inet
->cork
.rt
= NULL
;
1219 IP_INC_STATS(IPSTATS_MIB_OUTDISCARDS
);
1224 * Throw away all pending data on the socket.
1226 void ip_flush_pending_frames(struct sock
*sk
)
1228 struct inet_sock
*inet
= inet_sk(sk
);
1229 struct sk_buff
*skb
;
1231 while ((skb
= __skb_dequeue_tail(&sk
->sk_write_queue
)) != NULL
)
1234 inet
->cork
.flags
&= ~IPCORK_OPT
;
1235 if (inet
->cork
.opt
) {
1236 kfree(inet
->cork
.opt
);
1237 inet
->cork
.opt
= NULL
;
1239 if (inet
->cork
.rt
) {
1240 ip_rt_put(inet
->cork
.rt
);
1241 inet
->cork
.rt
= NULL
;
1247 * Fetch data from kernel space and fill in checksum if needed.
1249 static int ip_reply_glue_bits(void *dptr
, char *to
, int offset
,
1250 int len
, int odd
, struct sk_buff
*skb
)
1254 csum
= csum_partial_copy_nocheck(dptr
+offset
, to
, len
, 0);
1255 skb
->csum
= csum_block_add(skb
->csum
, csum
, odd
);
1260 * Generic function to send a packet as reply to another packet.
1261 * Used to send TCP resets so far. ICMP should use this function too.
1263 * Should run single threaded per socket because it uses the sock
1264 * structure to pass arguments.
1266 * LATER: switch from ip_build_xmit to ip_append_*
1268 void ip_send_reply(struct sock
*sk
, struct sk_buff
*skb
, struct ip_reply_arg
*arg
,
1271 struct inet_sock
*inet
= inet_sk(sk
);
1273 struct ip_options opt
;
1276 struct ipcm_cookie ipc
;
1278 struct rtable
*rt
= (struct rtable
*)skb
->dst
;
1280 if (ip_options_echo(&replyopts
.opt
, skb
))
1283 daddr
= ipc
.addr
= rt
->rt_src
;
1286 if (replyopts
.opt
.optlen
) {
1287 ipc
.opt
= &replyopts
.opt
;
1290 daddr
= replyopts
.opt
.faddr
;
1294 struct flowi fl
= { .nl_u
= { .ip4_u
=
1296 .saddr
= rt
->rt_spec_dst
,
1297 .tos
= RT_TOS(skb
->nh
.iph
->tos
) } },
1298 /* Not quite clean, but right. */
1300 { .sport
= skb
->h
.th
->dest
,
1301 .dport
= skb
->h
.th
->source
} },
1302 .proto
= sk
->sk_protocol
};
1303 if (ip_route_output_key(&rt
, &fl
))
1307 /* And let IP do all the hard work.
1309 This chunk is not reenterable, hence spinlock.
1310 Note that it uses the fact, that this function is called
1311 with locally disabled BH and that sk cannot be already spinlocked.
1314 inet
->tos
= skb
->nh
.iph
->tos
;
1315 sk
->sk_priority
= skb
->priority
;
1316 sk
->sk_protocol
= skb
->nh
.iph
->protocol
;
1317 ip_append_data(sk
, ip_reply_glue_bits
, arg
->iov
->iov_base
, len
, 0,
1318 &ipc
, rt
, MSG_DONTWAIT
);
1319 if ((skb
= skb_peek(&sk
->sk_write_queue
)) != NULL
) {
1320 if (arg
->csumoffset
>= 0)
1321 *((u16
*)skb
->h
.raw
+ arg
->csumoffset
) = csum_fold(csum_add(skb
->csum
, arg
->csum
));
1322 skb
->ip_summed
= CHECKSUM_NONE
;
1323 ip_push_pending_frames(sk
);
1331 void __init
ip_init(void)
1336 #if defined(CONFIG_IP_MULTICAST) && defined(CONFIG_PROC_FS)
1337 igmp_mc_proc_init();
1341 EXPORT_SYMBOL(ip_finish_output
);
1342 EXPORT_SYMBOL(ip_fragment
);
1343 EXPORT_SYMBOL(ip_generic_getfrag
);
1344 EXPORT_SYMBOL(ip_queue_xmit
);
1345 EXPORT_SYMBOL(ip_send_check
);
1347 #ifdef CONFIG_SYSCTL
1348 EXPORT_SYMBOL(sysctl_ip_default_ttl
);