aboutsummaryrefslogtreecommitdiff
path: root/net/ipv6/reassembly.c
AgeCommit message (Collapse)Author
2008-10-01ipv6: almost identical frag hashing funcs combinedIlpo Järvinen
$ diff-funcs ip6qhashfn reassembly.c netfilter/nf_conntrack_reasm.c --- reassembly.c:ip6qhashfn() +++ netfilter/nf_conntrack_reasm.c:ip6qhashfn() @@ -1,5 +1,5 @@ -static unsigned int ip6qhashfn(__be32 id, struct in6_addr *saddr, - struct in6_addr *daddr) +static unsigned int ip6qhashfn(__be32 id, const struct in6_addr *saddr, + const struct in6_addr *daddr) { u32 a, b, c; @@ -9,7 +9,7 @@ a += JHASH_GOLDEN_RATIO; b += JHASH_GOLDEN_RATIO; - c += ip6_frags.rnd; + c += nf_frags.rnd; __jhash_mix(a, b, c); a += (__force u32)saddr->s6_addr32[3]; And codiff xx.o.old xx.o.new: net/ipv6/netfilter/nf_conntrack_reasm.c: ip6qhashfn | -512 nf_hashfn | +6 nf_ct_frag6_gather | +36 3 functions changed, 42 bytes added, 512 bytes removed, diff: -470 net/ipv6/reassembly.c: ip6qhashfn | -512 ip6_hashfn | +7 ipv6_frag_rcv | +89 3 functions changed, 96 bytes added, 512 bytes removed, diff: -416 net/ipv6/reassembly.c: inet6_hash_frag | +510 1 function changed, 510 bytes added, diff: +510 Total: -376 Compile tested. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-25net: convert BUG_TRAP to generic WARN_ONIlpo Järvinen
Removes legacy reinvent-the-wheel type thing. The generic machinery integrates much better to automated debugging aids such as kerneloops.org (and others), and is unambiguous due to better naming. Non-intuively BUG_TRAP() is actually equal to WARN_ON() rather than BUG_ON() though some might actually be promoted to BUG_ON() but I left that to future. I could make at least one BUILD_BUG_ON conversion. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-06-28Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/wireless/iwlwifi/iwl4965-base.c
2008-06-27inet fragments: fix race between inet_frag_find and inet_frag_secret_rebuildPavel Emelyanov
The problem is that while we work w/o the inet_frags.lock even read-locked the secret rebuild timer may occur (on another CPU, since BHs are still disabled in the inet_frag_find) and change the rnd seed for ipv4/6 fragments. It was caused by my patch fd9e63544cac30a34c951f0ec958038f0529e244 ([INET]: Omit double hash calculations in xxx_frag_intern) late in the 2.6.24 kernel, so this should probably be queued to -stable. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-06-11net: remove CVS keywordsAdrian Bunk
This patch removes CVS keywords that weren't updated for a long time from comments. Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-19inet: Register fragmentation some ctls at read-only root.Pavel Emelyanov
Parts of fragments-related sysctls are read-only, but this is done by cloning all the tables and dropping write-bits from mode. Do the same but with read-only root. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-19ipv6: In fragmentation code, handle error returned from register_pernet_subsys.Pavel Emelyanov
The error code is ignored now, but ipv6 is a module and one can be loaded under memory pressure, so the error may occur (in theory). Besides, I'm going to handle error returned from registering a read-only part of the table, so ignoring this one, while handing the other one would look strange. (However, this possibility of error is rather small, so I'm not sure whether this is a candidate for current net tree). Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-19inet: Rename fragmentation sysctl-related functions/variables.Pavel Emelyanov
The fragments sysctls also contains some, that are to be visible, but read-only in net namespaces. The naming in net/core/sysctl_net_core.c is - tables, that are to be registered in namespaces have a "ns" word in their names. So rename ones in ipv4/ip_fragment.c and ipv6/reassembly.c to fit this. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-05-02netns: Fix reassembly timer to use the right namespaceDaniel Lezcano
This trivial fix retrieves the network namespace from frag queue and use it to get the network device in the right namespace. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-28[NET]: Rename inet_frag.h identifiers COMPLETE, FIRST_IN, LAST_IN to INET_FRAG_*Joe Perches
On Fri, 2008-03-28 at 03:24 -0700, Andrew Morton wrote: > they should all be renamed. Done for include/net and net Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-26[NET] NETNS: Omit net_device->nd_net without CONFIG_NET_NS.YOSHIFUJI Hideaki
Introduce per-net_device inlines: dev_net(), dev_net_set(). Without CONFIG_NET_NS, no namespace other than &init_net exists. Let's explicitly define them to help compiler optimizations. Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
2008-01-28[NETNS][FRAGS]: Make the pernet subsystem for fragments.Pavel Emelyanov
On namespace start we mainly prepare the ctl variables. When the namespace is stopped we have to kill all the fragments that point to this namespace. The inet_frags_exit_net() handles it. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETNS][FRAGS]: Make the LRU list per namespace.Pavel Emelyanov
The inet_frags.lru_list is used for evicting only, so we have to make it per-namespace, to evict only those fragments, who's namespace exceeded its high threshold, but not the whole hash. Besides, this helps to avoid long loops in evictor. The spinlock is not per-namespace because it protects the hash table as well, which is global. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETNS][FRAGS]: Isolate the secret interval from namespaces.Pavel Emelyanov
Since we have one hashtable to lookup the fragment, having different secret_interval-s for hash rebuild doesn't make sense, so move this one to inet_frags. The inet_frags_ctl becomes empty after this, so remove it. The appropriate ctl table is kept read-only in namespaces. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETNS][FRAGS]: Make thresholds work in namespaces.Pavel Emelyanov
This is the same as with the timeout variable. Currently, after exceeding the high threshold _all_ the fragments are evicted, but it will be fixed in later patch. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETNS][FRAGS]: Make the net.ipv4.ipfrag_timeout work in namespaces.Pavel Emelyanov
Move it to the netns_frags, adjust the usage and make the appropriate ctl table writable. Now fragment, that live in different namespaces can live for different times. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETNS][FRAGS]: Duplicate sysctl tables for new namespaces.Pavel Emelyanov
Each namespace has to have own tables to tune their different parameters, so duplicate the tables and register them. All the tables in sub-namespaces are temporarily made read-only. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETNS][FRAGS]: Make the mem counter per-namespace.Pavel Emelyanov
This is also simple, but introduces more changes, since then mem counter is altered in more places. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETNS][FRAGS]: Make the nqueues counter per-namespace.Pavel Emelyanov
This is simple - just move the variable from struct inet_frags to struct netns_frags and adjust the usage appropriately. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETNS][FRAGS]: Make the inet_frag_queue lookup work in namespaces.Pavel Emelyanov
Since fragment management code is consolidated, we cannot have the pointer from inet_frag_queue to struct net, since we must know what king of fragment this is. So, I introduce the netns_frags structure. This one is currently empty, but will be eventually filled with per-namespace attributes. Each inet_frag_queue is tagged with this one. The conntrack_reasm is not "netns-izated", so it has one static netns_frags instance to keep working in init namespace. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETNS][FRAGS]: Move ctl tables around.Pavel Emelyanov
This is a preparation for sysctl netns-ization. Move the ctl tables to the files, where the tuning variables reside. Plus make the helpers to register the tables. This will simplify the later patches and will keep similar things closer to each other. ipv4, ipv6 and conntrack_reasm are patched differently, but the result is all the tables are in appropriate files. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[IPV6]: Fix ip6_frag ctlDaniel Lezcano
Alexey Dobriyan reported an oops when unsharing the network indefinitely inside a loop. This is because the ip6_frag is not per namespace while the ctls are. That happens at the fragment timer expiration: inet_frag_secret_rebuild function is called and this one restarts the timer using the value stored inside the sysctl field. "mod_timer(&f->secret_timer, now + f->ctl->secret_interval);" When the network is unshared, ip6_frag.ctl is initialized with the new sysctl instances, but ip6_frag has only one instance. A race in this case will appear because f->ctl can be modified during the read access in the timer callback. Until the ip6_frag is not per namespace, I discard the assignation to the ctl field of ip6_frags in ip6_frag_sysctl_init when the network namespace is not the init net. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[NETNS][IPV6]: Make ip6_frags per namespace.Daniel Lezcano
The ip6_frags is moved to the network namespace structure. Because there can be multiple instances of the network namespaces, and the ip6_frags is no longer a global static variable, a helper function has been added to facilitate the initialization of the variables. Until the ipv6 protocol is not per namespace, the variables are accessed relatively from the initial network namespace. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28[IPV6]: make frag to return an error at initializationDaniel Lezcano
This patch makes the frag_init to return an error code, so the af_inet6 module can handle the error. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-17[INET]: Consolidate frag queues freeingPavel Emelyanov
Since we now allocate the queues in inet_fragment.c, we can safely free it in the same place. The ->destructor callback thus becomes optional for inet_frags. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-17[INET]: Remove no longer needed ->equal callbackPavel Emelyanov
Since this callback is used to check for conflicts in hashtable when inserting a newly created frag queue, we can do the same by checking for matching the queue with the argument, used to create one. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-17[INET]: Consolidate xxx_find() in fragment managementPavel Emelyanov
Here we need another callback ->match to check whether the entry found in hash matches the key passed. The key used is the same as the creation argument for inet_frag_create. Yet again, this ->match is the same for netfilter and ipv6. Running a frew steps forward - this callback will later replace the ->equal one. Since the inet_frag_find() uses the already consolidated inet_frag_create() remove the xxx_frag_create from protocol codes. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-17[INET]: Consolidate xxx_frag_create()Pavel Emelyanov
This one uses the xxx_frag_intern() and xxx_frag_alloc() routines, which are already consolidated, so remove them from protocol code (as promised). The ->constructor callback is used to init the rest of the frag queue and it is the same for netfilter and ipv6. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-17[INET]: Consolidate xxx_frag_alloc()Pavel Emelyanov
Just perform the kzalloc() allocation and setup common fields in the inet_frag_queue(). Then return the result to the caller to initialize the rest. The inet_frag_alloc() may return NULL, so check the return value before doing the container_of(). This looks ugly, but the xxx_frag_alloc() will be removed soon. The xxx_expire() timer callbacks are patches, because the argument is now the inet_frag_queue, not the protocol specific queue. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-17[INET]: Consolidate xxx_frag_internPavel Emelyanov
This routine checks for the existence of a given entry in the hash table and inserts the new one if needed. The ->equal callback is used to compare two frag_queue-s together, but this one is temporary and will be removed later. The netfilter code and the ipv6 one use the same routine to compare frags. The inet_frag_intern() always returns non-NULL pointer, so convert the inet_frag_queue into protocol specific one (with the container_of) without any checks. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-17[INET]: Omit double hash calculations in xxx_frag_internPavel Emelyanov
Since the hash value is already calculated in xxx_find, we can simply use it later. This is already done in netfilter code, so make the same in ipv4 and ipv6. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[IPV6]: Replace sk_buff ** with sk_buff * in input handlersHerbert Xu
With all the users of the double pointers removed from the IPv6 input path, this patch converts all occurances of sk_buff ** to sk_buff * in IPv6 input handlers. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[INET]: Consolidate the xxx_putPavel Emelyanov
These ones use the generic data types too, so move them in one place. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[INET]: Small cleanup for xxx_put after evictor consolidationPavel Emelyanov
After the evictor code is consolidated there is no need in passing the extra pointer to the xxx_put() functions. The only place when it made sense was the evictor code itself. Maybe this change must got with the previous (or with the next) patch, but I try to make them shorter as much as possible to simplify the review (but they are still large anyway), so this change goes in a separate patch. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[INET]: Consolidate the xxx_evictorPavel Emelyanov
The evictors collect some statistics for ipv4 and ipv6, so make it return the number of evicted queues and account them all at once in the caller. The XXX_ADD_STATS_BH() macros are just for this case, but maybe there are places in code, that can make use of them as well. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[INET]: Consolidate the xxx_frag_destroyPavel Emelyanov
To make in possible we need to know the exact frag queue size for inet_frags->mem management and two callbacks: * to destoy the skb (optional, used in conntracks only) * to free the queue itself (mandatory, but later I plan to move the allocation and the destruction of frag_queues into the common place, so this callback will most likely be optional too). Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[INET]: Consolidate xxx_the secret_rebuildPavel Emelyanov
This code works with the generic data types as well, so move this into inet_fragment.c This move makes it possible to hide the secret_timer management and the secret_rebuild routine completely in the inet_fragment.c Introduce the ->hashfn() callback in inet_frags() to get the hashfun for a given inet_frag_queue() object. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[INET]: Consolidate the xxx_frag_killPavel Emelyanov
Since now all the xxx_frag_kill functions now work with the generic inet_frag_queue data type, this can be moved into a common place. The xxx_unlink() code is moved as well. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[INET]: Collect common frag sysctl variables togetherPavel Emelyanov
Some sysctl variables are used to tune the frag queues management and it will be useful to work with them in a common way in the future, so move them into one structure, moreover they are the same for all the frag management codes. I don't place them in the existing inet_frags object, introduced in the previous patch for two reasons: 1. to keep them in the __read_mostly section; 2. not to export the whole inet_frags objects outside. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[INET]: Collect frag queues management objects togetherPavel Emelyanov
There are some objects that are common in all the places which are used to keep track of frag queues, they are: * hash table * LRU list * rw lock * rnd number for hash function * the number of queues * the amount of memory occupied by queues * secret timer Move all this stuff into one structure (struct inet_frags) to make it possible use them uniformly in the future. Like with the previous patch this mostly consists of hunks like - write_lock(&ipfrag_lock); + write_lock(&ip4_frags.lock); To address the issue with exporting the number of queues and the amount of memory occupied by queues outside the .c file they are declared in, I introduce a couple of helpers. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[INET]: Move common fields from frag_queues in one place.Pavel Emelyanov
Introduce the struct inet_frag_queue in include/net/inet_frag.h file and place there all the common fields from three structs: * struct ipq in ipv4/ip_fragment.c * struct nf_ct_frag6_queue in nf_conntrack_reasm.c * struct frag_queue in ipv6/reassembly.c After this, replace these fields on appropriate structures with this structure instance and fix the users to use correct names i.e. hunks like - atomic_dec(&fq->refcnt); + atomic_dec(&fq->q.refcnt); (these occupy most of the patch) Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-15[IPV6]: Make ipv6_frag_rcv return the same packetHerbert Xu
This patch implements the same change taht was done to ip_defrag. It makes ipv6_frag_rcv return the last packet received of a train of fragments rather than the head of that sequence. This allows us to get rid of the sk_buff ** argument later. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10[NET]: Make the device list and device lookups per namespace.Eric W. Biederman
This patch makes most of the generic device layer network namespace safe. This patch makes dev_base_head a network namespace variable, and then it picks up a few associated variables. The functions: dev_getbyhwaddr dev_getfirsthwbytype dev_get_by_flags dev_get_by_name __dev_get_by_name dev_get_by_index __dev_get_by_index dev_ioctl dev_ethtool dev_load wireless_process_ioctl were modified to take a network namespace argument, and deal with it. vlan_ioctl_set and brioctl_set were modified so their hooks will receive a network namespace argument. So basically anthing in the core of the network stack that was affected to by the change of dev_base was modified to handle multiple network namespaces. The rest of the network stack was simply modified to explicitly use &init_net the initial network namespace. This can be fixed when those components of the network stack are modified to handle multiple network namespaces. For now the ifindex generator is left global. Fundametally ifindex numbers are per namespace, or else we will have corner case problems with migration when we get that far. At the same time there are assumptions in the network stack that the ifindex of a network device won't change. Making the ifindex number global seems a good compromise until the network stack can cope with ifindex changes when you change namespaces, and the like. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: unions of just one member don't get anything done, kill themArnaldo Carvalho de Melo
Renaming skb->h to skb->transport_header, skb->nh to skb->network_header and skb->mac to skb->mac_header, to match the names of the associated helpers (skb[_[re]set]_{transport,network,mac}_header). Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_network_header_lenArnaldo Carvalho de Melo
For the common sequence "skb->h.raw - skb->nh.raw", similar to skb->mac_len, that is precalculated tho, don't think we need to bloat skb with one more member, so just use this new helper, reducing the number of non-skbuff.h references to the layer headers even more. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_transport_header(skb)Arnaldo Carvalho de Melo
For the places where we need a pointer to the transport header, it is still legal to touch skb->h.raw directly if just adding to, subtracting from or setting it to another layer header. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_transport_offset()Arnaldo Carvalho de Melo
For the quite common 'skb->h.raw - skb->data' sequence. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_reset_transport_header(skb)Arnaldo Carvalho de Melo
For the common, open coded 'skb->h.raw = skb->data' operation, so that we can later turn skb->h.raw into a offset, reducing the size of struct sk_buff in 64bit land while possibly keeping it as a pointer on 32bit. This one touches just the most simple cases: skb->h.raw = skb->data; skb->h.raw = {skb_push|[__]skb_pull}() The next ones will handle the slightly more "complex" cases. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce ipv6_hdr(), remove skb->nh.ipv6hArnaldo Carvalho de Melo
Now the skb->nh union has just one member, .raw, i.e. it is just like the skb->mac union, strange, no? I'm just leaving it like that till the transport layer is done with, when we'll rename skb->mac.raw to skb->mac_header (or ->mac_header_offset?), ditto for ->{h,nh}. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-25[SK_BUFF]: Introduce skb_network_header()Arnaldo Carvalho de Melo
For the places where we need a pointer to the network header, it is still legal to touch skb->nh.raw directly if just adding to, subtracting from or setting it to another layer header. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>