Cross Reference: /net/core/filter.c

History log of /net/core/filter.c
Revision	Date	Author	Comments
ed13998c319b050fc9abdb73915859dfdbe1fb38	05-Jun-2013	Nicolas Dichtel <nicolas.dichtel@6wind.com>	sock_diag: fix filter code sent to userspace Filters need to be translated to real BPF code for userland, like SO_GETFILTER. Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net>
3e5289d5e3f98b7b5b8cac32e9e5a7004c067436	19-Mar-2013	Daniel Borkmann <dborkman@redhat.com>	filter: add ANC_PAY_OFFSET instruction for loading payload start offset It is very useful to do dynamic truncation of packets. In particular, we're interested to push the necessary header bytes to the user space and cut off user payload that should probably not be transferred for some reasons (e.g. privacy, speed, or others). With the ancillary extension PAY_OFFSET, we can load it into the accumulator, and return it. E.g. in bpfc syntax ... ld #poff ; { 0x20, 0, 0, 0xfffff034 }, ret a ; { 0x16, 0, 0, 0x00000000 }, ... as a filter will accomplish this without having to do a big hackery in a BPF filter itself. Follow-up JIT implementations are welcome. Thanks to Eric Dumazet for suggesting and discussing this during the Netfilter Workshop in Copenhagen. Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
d59577b6ffd313d0ab3be39cb1ab47e29bdc9182	16-Jan-2013	Vincent Bernat <bernat@luffy.cx>	sk-filter: Add ability to lock a socket filter program While a privileged program can open a raw socket, attach some restrictive filter and drop its privileges (or send the socket to an unprivileged program through some Unix socket), the filter can still be removed or modified by the unprivileged program. This commit adds a socket option to lock the filter (SO_LOCK_FILTER) preventing any modification of a socket filter program. This is similar to OpenBSD BIOCLOCK ioctl on bpf sockets, except even root is not allowed change/drop the filter. The state of the lock can be read with getsockopt(). No error is triggered if the state is not changed. -EPERM is returned when a user tries to remove the lock or to change/remove the filter while the lock is active. The check is done directly in sk_attach_filter() and sk_detach_filter() and does not affect only setsockopt() syscall. Signed-off-by: Vincent Bernat <bernat@luffy.cx> Signed-off-by: David S. Miller <davem@davemloft.net>
aa1113d9f85da59dcbdd32aeb5d71da566e46def	28-Dec-2012	Daniel Borkmann <dborkman@redhat.com>	net: filter: return -EINVAL if BPF_S_ANC* operation is not supported Currently, we return -EINVAL for malformed or wrong BPF filters. However, this is not done for BPF_S_ANC* operations, which makes it more difficult to detect if it's actually supported or not by the BPF machine. Therefore, we should also return -EINVAL if K is within the SKF_AD_OFF universe and the ancillary operation did not match. Why exactly is it needed? If tools such as libpcap/tcpdump want to make use of new ancillary operations (like filtering VLAN in kernel space), there is currently no sane way to test if this feature / BPF_S_ANC* op is present or not, since no error is returned. This patch will make life easier for that and allow for a proper usage for user space applications. There was concern, if this patch will break userland. Short answer: Yes and no. Long answer: It will "break" only for code that calls ... { BPF_LD \| BPF_(W\|H\|B) \| BPF_ABS, 0, 0, <K> }, ... where <K> is in [0xfffff000, 0xffffffff] _and_ <K> is not an ancillary. And here comes the BUT: assuming some old code will have such an instruction where <K> is between [0xfffff000, 0xffffffff] and it doesn't know ancillary operations, then this will give a non-expected / unwanted behavior as well (since we do not return the BPF machine with 0 after a failed load_pointer(), which was the case before introducing ancillary operations, but load sth. into the accumulator instead, and continue with the next instruction, for instance). Thus, user space code would already have been broken by introducing ancillary operations into the BPF machine per se. Code that does such a direct load, e.g. "load word at packet offset 0xffffffff into accumulator" ("ld [0xffffffff]") is quite broken, isn't it? The whole assumption of ancillary operations is that no-one intentionally calls things like "ld [0xffffffff]" and expect this word to be loaded from such a packet offset. Hence, we can also safely make use of this feature testing patch and facilitate application development. Therefore, at least from this patch onwards, we have for sure a check whether current or in future implemented BPF_S_ANC* ops are supported in the kernel. Patch was tested on x86_64. (Thanks to Eric for the previous review.) Cc: Eric Dumazet <eric.dumazet@gmail.com> Reported-by: Ani Sinha <ani@aristanetworks.com> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
a8fc92778080c845eaadc369a0ecf5699a03bef0	01-Nov-2012	Pavel Emelyanov <xemul@parallels.com>	sk-filter: Add ability to get socket filter program (v2) The SO_ATTACH_FILTER option is set only. I propose to add the get ability by using SO_ATTACH_FILTER in getsockopt. To be less irritating to eyes the SO_GET_FILTER alias to it is declared. This ability is required by checkpoint-restore project to be able to save full state of a socket. There are two issues with getting filter back. First, kernel modifies the sock_filter->code on filter load, thus in order to return the filter element back to user we have to decode it into user-visible constants. Fortunately the modification in question is interconvertible. Second, the BPF_S_ALU_DIV_K code modifies the command argument k to speed up the run-time division by doing kernel_k = reciprocal(user_k). Bad news is that different user_k may result in same kernel_k, so we can't get the original user_k back. Good news is that we don't have to do it. What we need to is calculate a user2_k so, that reciprocal(user2_k) == reciprocal(user_k) == kernel_k i.e. if it's re-loaded back the compiled again value will be exactly the same as it was. That said, the user2_k can be calculated like this user2_k = reciprocal(kernel_k) with an exception, that if kernel_k == 0, then user2_k == 1. The optlen argument is treated like this -- when zero, kernel returns the amount of sock_fprog elements in filter, otherwise it should be large enough for the sock_fprog array. changes since v1: * Declared SO_GET_FILTER in all arch headers * Added decode of vlan-tag codes Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: David S. Miller <davem@davemloft.net>
f3335031b9452baebfe49b8b5e55d3fe0c4677d1	27-Oct-2012	Eric Dumazet <edumazet@google.com>	net: filter: add vlan tag access BPF filters lack ability to access skb->vlan_tci This patch adds two new ancillary accessors : SKF_AD_VLAN_TAG (44) mapped to vlan_tx_tag_get(skb) SKF_AD_VLAN_TAG_PRESENT (48) mapped to vlan_tx_tag_present(skb) This allows libpcap/tcpdump to use a kernel filter instead of having to fallback to accept all packets, then filter them in user space. Signed-off-by: Eric Dumazet <edumazet@google.com> Suggested-by: Ani Sinha <ani@aristanetworks.com> Suggested-by: Daniel Borkmann <danborkmann@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
9e49e88958feb41ec701fa34b44723dabadbc28c	24-Sep-2012	Daniel Borkmann <dxchgb@gmail.com>	filter: add XOR instruction for use with X/K SKF_AD_ALU_XOR_X has been added a while ago, but as an 'ancillary' operation that is invoked through a negative offset in K within BPF load operations. Since BPF_MOD has recently been added, BPF_XOR should also be part of the common ALU operations. Removing SKF_AD_ALU_XOR_X might not be an option since this is exposed to user space. Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
b6069a95706ca5738be3f5d90fd286cbd13ac695	08-Sep-2012	Eric Dumazet <edumazet@google.com>	filter: add MOD operation Add a new ALU opcode, to compute a modulus. Commit ffe06c17afbbb used an ancillary to implement XOR_X, but here we reserve one of the available ALU opcode to implement both MOD_X and MOD_K Signed-off-by: Eric Dumazet <edumazet@google.com> Suggested-by: George Bakos <gbakos@alpinista.org> Cc: Jay Schulist <jschlst@samba.org> Cc: Jiri Pirko <jpirko@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
c93bdd0e03e848555d144eb44a1f275b871a8dd5	01-Aug-2012	Mel Gorman <mgorman@suse.de>	netvm: allow skb allocation to use PFMEMALLOC reserves Change the skb allocation API to indicate RX usage and use this to fall back to the PFMEMALLOC reserve when needed. SKBs allocated from the reserve are tagged in skb->pfmemalloc. If an SKB is allocated from the reserve and the socket is later found to be unrelated to page reclaim, the packet is dropped so that the memory remains available for page reclaim. Network protocols are expected to recover from this packet loss. [a.p.zijlstra@chello.nl: Ideas taken from various patches] [davem@davemloft.net: Use static branches, coding style corrections] [sebastian@breakpoint.cc: Avoid unnecessary cast, fix !CONFIG_NET build] Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: David S. Miller <davem@davemloft.net> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Mel Gorman <mgorman@suse.de> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
c6c4b97c6b7003e8082dd43db224c1d1f7a24aa2	08-Jun-2012	Randy Dunlap <rdunlap@xenotime.net>	net/core: fix kernel-doc warnings Fix kernel-doc warnings in net/core: Warning(net/core/skbuff.c:3368): No description found for parameter 'delta_truesize' Warning(net/core/filter.c:628): No description found for parameter 'pfp' Warning(net/core/filter.c:628): Excess function parameter 'sk' description in 'sk_unattached_filter_create' Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: David S. Miller <davem@davemloft.net>
95c961747284a6b83a5e2d81240e214b0fa3464d	15-Apr-2012	Eric Dumazet <eric.dumazet@gmail.com>	net: cleanup unsigned to unsigned int Use of "unsigned int" is preferred to bare "unsigned" in net tree. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
46b325c7eb01482674406701825ff67f561ccdd4	12-Apr-2012	Will Drewry <wad@chromium.org>	sk_run_filter: add BPF_S_ANC_SECCOMP_LD_W Introduces a new BPF ancillary instruction that all LD calls will be mapped through when skb_run_filter() is being used for seccomp BPF. The rewriting will be done using a secondary chk_filter function that is run after skb_chk_filter. The code change is guarded by CONFIG_SECCOMP_FILTER which is added, along with the seccomp_bpf_load() function later in this series. This is based on http://lkml.org/lkml/2012/3/2/141 Suggested-by: Indan Zupancic <indan@nul.nu> Signed-off-by: Will Drewry <wad@chromium.org> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Eric Paris <eparis@redhat.com> v18: rebase ... v15: include seccomp.h explicitly for when seccomp_bpf_load exists. v14: First cut using a single additional instruction ... v13: made bpf functions generic. Signed-off-by: James Morris <james.l.morris@oracle.com>
ffe06c17afbbbd4d73cdc339419be232847d667a	31-Mar-2012	Jiri Pirko <jpirko@redhat.com>	filter: add XOR operation Add XOR instruction fo BPF machine. Needed for computing packet hashes. Signed-off-by: Jiri Pirko <jpirko@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
302d663740cfaf2c364df6bb61cd339014ed714c	31-Mar-2012	Jiri Pirko <jpirko@redhat.com>	filter: Allow to create sk-unattached filters Today, BPF filters are bind to sockets. Since BPF machine becomes handy for other purposes, this patch allows to create unattached filter. Signed-off-by: Jiri Pirko <jpirko@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
f03fb3f455c6c3a3dfcef6c7f2dcab104c813f4b	30-Mar-2012	Jan Seiffert <kaffeemonster@googlemail.com>	bpf jit: Make the filter.c::__load_pointer helper non-static for the jits The function is renamed to make it a little more clear what it does. It is not added to any .h because it is not for general consumption, only for bpf internal use (and so by the jits). Signed-of-by: Jan Seiffert <kaffeemonster@googlemail.com> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
9ffc93f203c18a70623f21950f1dd473c9ec48cd	28-Mar-2012	David Howells <dhowells@redhat.com>	Remove all #inclusions of asm/system.h Remove all #inclusions of asm/system.h preparatory to splitting and killing it. Performed with the following command: perl -p -i -e 's!^#\sinclude\s<asm/system[.]h>.\n!!' `grep -Irl '^#\sinclude\s<asm/system[.]h>' ` Signed-off-by: David Howells <dhowells@redhat.com>
4f25af27827080c3163e59c7af1ca84a05ce121c	17-Oct-2011	Dan Carpenter <dan.carpenter@oracle.com>	filter: use unsigned int to silence static checker warning This is just a cleanup. My testing version of Smatch warns about this: net/core/filter.c +380 check_load_and_stores(6) warn: check 'flen' for negative values flen comes from the user. We try to clamp the values here between 1 and BPF_MAXINSNS but the clamp doesn't work because it could be negative. This is a bug, but it's not exploitable. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
a9b3cd7f323b2e57593e7215362a7b02fc933e3a	01-Aug-2011	Stephen Hemminger <shemminger@vyatta.com>	rcu: convert uses of rcu_assign_pointer(x, NULL) to RCU_INIT_POINTER When assigning a NULL value to an RCU protected pointer, no barrier is needed. The rcu_assign_pointer, used to handle that but will soon change to not handle the special case. Convert all rcu_assign_pointer of NULL value. //smpl @@ expression P; @@ - rcu_assign_pointer(P, NULL) + RCU_INIT_POINTER(P, NULL) // </smpl> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
86e4ca66e81bba0f8640f1fa19b8b8f72cbd0561	26-May-2011	David S. Miller <davem@davemloft.net>	bug.h: Move ratelimit warn interfaces to ratelimit.h As reported by Ingo Molnar, we still have configuration combinations where use of the WARN_RATELIMIT interfaces break the build because dependencies don't get met. Instead of going down the long road of trying to make it so that ratelimit.h can get included by kernel.h or asm-generic/bug.h, just move the interface into ratelimit.h and make users have to include that. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
6c4a5cb219520c7bc937ee186ca53f03733bd09f	21-May-2011	Joe Perches <joe@perches.com>	net: filter: Use WARN_RATELIMIT A mis-configured filter can spam the logs with lots of stack traces. Rate-limit the warnings and add printout of the bogus filter information. Original-patch-by: Ben Greear <greearb@candelatech.com> Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
0a14842f5a3c0e88a1e59fac5c3025db39721f74	20-Apr-2011	Eric Dumazet <eric.dumazet@gmail.com>	net: filter: Just In Time compiler for x86-64 In order to speedup packet filtering, here is an implementation of a JIT compiler for x86_64 It is disabled by default, and must be enabled by the admin. echo 1 >/proc/sys/net/core/bpf_jit_enable It uses module_alloc() and module_free() to get memory in the 2GB text kernel range since we call helpers functions from the generated code. EAX : BPF A accumulator EBX : BPF X accumulator RDI : pointer to skb (first argument given to JIT function) RBP : frame pointer (even if CONFIG_FRAME_POINTER=n) r9d : skb->len - skb->data_len (headlen) r8 : skb->data To get a trace of generated code, use : echo 2 >/proc/sys/net/core/bpf_jit_enable Example of generated code : # tcpdump -p -n -s 0 -i eth1 host 192.168.20.0/24 flen=18 proglen=147 pass=3 image=ffffffffa00b5000 JIT code: ffffffffa00b5000: 55 48 89 e5 48 83 ec 60 48 89 5d f8 44 8b 4f 60 JIT code: ffffffffa00b5010: 44 2b 4f 64 4c 8b 87 b8 00 00 00 be 0c 00 00 00 JIT code: ffffffffa00b5020: e8 24 7b f7 e0 3d 00 08 00 00 75 28 be 1a 00 00 JIT code: ffffffffa00b5030: 00 e8 fe 7a f7 e0 24 00 3d 00 14 a8 c0 74 49 be JIT code: ffffffffa00b5040: 1e 00 00 00 e8 eb 7a f7 e0 24 00 3d 00 14 a8 c0 JIT code: ffffffffa00b5050: 74 36 eb 3b 3d 06 08 00 00 74 07 3d 35 80 00 00 JIT code: ffffffffa00b5060: 75 2d be 1c 00 00 00 e8 c8 7a f7 e0 24 00 3d 00 JIT code: ffffffffa00b5070: 14 a8 c0 74 13 be 26 00 00 00 e8 b5 7a f7 e0 24 JIT code: ffffffffa00b5080: 00 3d 00 14 a8 c0 75 07 b8 ff ff 00 00 eb 02 31 JIT code: ffffffffa00b5090: c0 c9 c3 BPF program is 144 bytes long, so native program is almost same size ;) (000) ldh [12] (001) jeq #0x800 jt 2 jf 8 (002) ld [26] (003) and #0xffffff00 (004) jeq #0xc0a81400 jt 16 jf 5 (005) ld [30] (006) and #0xffffff00 (007) jeq #0xc0a81400 jt 16 jf 17 (008) jeq #0x806 jt 10 jf 9 (009) jeq #0x8035 jt 10 jf 17 (010) ld [28] (011) and #0xffffff00 (012) jeq #0xc0a81400 jt 16 jf 13 (013) ld [38] (014) and #0xffffff00 (015) jeq #0xc0a81400 jt 16 jf 17 (016) ret #65535 (017) ret #0 Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Ben Hutchings <bhutchings@solarflare.com> Cc: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: David S. Miller <davem@davemloft.net>
25985edcedea6396277003854657b5f3cb31a628	31-Mar-2011	Lucas De Marchi <lucas.demarchi@profusion.mobi>	Fix common misspellings Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
80f8f1027b99660897bdeaeae73002185d829906	18-Jan-2011	Eric Dumazet <eric.dumazet@gmail.com>	net: filter: dont block softirqs in sk_run_filter() Packet filter (BPF) doesnt need to disable softirqs, being fully re-entrant and lock-less. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
697d0e338c7fd392cf73bf120150ab6e5516a3a3	08-Jan-2011	Randy Dunlap <randy.dunlap@oracle.com>	net: fix kernel-doc warning in core/filter.c Fix new kernel-doc notation warning in net/core/filter.c: Warning(net/core/filter.c:172): No description found for parameter 'fentry' Warning(net/core/filter.c:172): Excess function parameter 'filter' description in 'sk_run_filter' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
12b16dadbc2406144d408754f96d0f44aa016239	15-Dec-2010	Eric Dumazet <eric.dumazet@gmail.com>	filter: optimize accesses to ancillary data We can translate pseudo load instructions at filter check time to dedicated instructions to speed up filtering and avoid one switch(). libpcap currently uses SKF_AD_PROTOCOL, but custom filters probably use other ancillary accesses. Note : I made the assertion that ancillary data was always accessed with BPF_LD\|BPF_?\|BPF_ABS instructions, not with BPF_LD\|BPF_?\|BPF_IND ones (offset given by K constant, not by K + X register) On x86_64, this saves a few bytes of text : # size net/core/filter.o.* text data bss dec hex filename 4864 0 0 4864 1300 net/core/filter.o.new 4944 0 0 4944 1350 net/core/filter.o.old Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
4bc65dd8d88671712d71592a83374cfb0b5fce7a	07-Dec-2010	Eric Dumazet <eric.dumazet@gmail.com>	filter: use size of fetched data in __load_pointer() __load_pointer() checks data we fetch from skb is included in head portion, but assumes we fetch one byte, instead of up to four. This wont crash because we have extra bytes (struct skb_shared_info) after head, but this can read uninitialized bytes. Fix this using size of the data (1, 2, 4 bytes) in the test. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
62ab0812137ec4f9884dd7de346238841ac03283	06-Dec-2010	Eric Dumazet <eric.dumazet@gmail.com>	filter: constify sk_run_filter() sk_run_filter() doesnt write on skb, change its prototype to reflect this. Fix two af_packet comments. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2d5311e4e8272fd398fc1cf278f12fd6dee4074b	01-Dec-2010	Eric Dumazet <eric.dumazet@gmail.com>	filter: add a security check at install time We added some security checks in commit 57fe93b374a6 (filter: make sure filters dont read uninitialized memory) to close a potential leak of kernel information to user. This added a potential extra cost at run time, while we can perform a check of the filter itself, to make sure a malicious user doesnt try to abuse us. This patch adds a check_loads() function, whole unique purpose is to make this check, allocating a temporary array of mask. We scan the filter and propagate a bitmask information, telling us if a load M(K) is allowed because a previous store M(K) is guaranteed. (So that sk_run_filter() can possibly not read unitialized memory) Note: this can uncover application bug, denying a filter attach, previously allowed. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Dan Rosenberg <drosenberg@vsecurity.com> Cc: Changli Gao <xiaosuo@gmail.com> Acked-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
da2033c282264bfba4e339b7cb3df62adb5c5fc8	30-Nov-2010	Eric Dumazet <eric.dumazet@gmail.com>	filter: add SKF_AD_RXHASH and SKF_AD_CPU Add SKF_AD_RXHASH and SKF_AD_CPU to filter ancillary mechanism, to be able to build advanced filters. This can help spreading packets on several sockets with a fast selection, after RPS dispatch to N cpus for example, or to catch a percentage of flows in one queue. tcpdump -s 500 "cpu = 1" : [0] ld CPU [1] jeq #1 jt 2 jf 3 [2] ret #500 [3] ret #0 # take 12.5 % of flows (average) tcpdump -s 1000 "rxhash & 7 = 2" : [0] ld RXHASH [1] and #7 [2] jeq #2 jt 3 jf 4 [3] ret #1000 [4] ret #0 Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Rui <wirelesser@gmail.com> Acked-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
46bcf14f44d8f31ecfdc8b6708ec15a3b33316d9	06-Dec-2010	Eric Dumazet <eric.dumazet@gmail.com>	filter: fix sk_filter rcu handling Pavel Emelyanov tried to fix a race between sk_filter_(de\|at)tach and sk_clone() in commit 47e958eac280c263397 Problem is we can have several clones sharing a common sk_filter, and these clones might want to sk_filter_attach() their own filters at the same time, and can overwrite old_filter->rcu, corrupting RCU queues. We can not use filter->rcu without being sure no other thread could do the same thing. Switch code to a more conventional ref-counting technique : Do the atomic decrement immediately and queue one rcu call back when last reference is released. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
c26aed40f4fd18f86bcc6aba557cab700b129b73	18-Nov-2010	Eric Dumazet <eric.dumazet@gmail.com>	filter: use reciprocal divide At compile time, we can replace the DIV_K instruction (divide by a constant value) by a reciprocal divide. At exec time, the expensive divide is replaced by a multiply, a less expensive operation on most processors. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
8c1592d68bc89248bfd0ee287648f41c1370d826	18-Nov-2010	Eric Dumazet <eric.dumazet@gmail.com>	filter: cleanup codes[] init Starting the translated instruction to 1 instead of 0 allows us to remove one descrement at check time and makes codes[] array init cleaner. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
93aaae2e01e57483256b7da05c9a7ebd65ad4686	19-Nov-2010	Eric Dumazet <eric.dumazet@gmail.com>	filter: optimize sk_run_filter Remove pc variable to avoid arithmetic to compute fentry at each filter instruction. Jumps directly manipulate fentry pointer. As the last instruction of filter[] is guaranteed to be a RETURN, and all jumps are before the last instruction, we dont need to check filter bounds (number of instructions in filter array) at each iteration, so we remove it from sk_run_filter() params. On x86_32 remove f_k var introduced in commit 57fe93b374a6b871 (filter: make sure filters dont read uninitialized memory) Note : We could use a CONFIG_ARCH_HAS_{FEW\|MANY}_REGISTERS in order to avoid too many ifdefs in this code. This helps compiler to use cpu registers to hold fentry and A accumulator. On x86_32, this saves 401 bytes, and more important, sk_run_filter() runs much faster because less register pressure (One less conditional branch per BPF instruction) # size net/core/filter.o net/core/filter_pre.o text data bss dec hex filename 2948 0 0 2948 b84 net/core/filter.o 3349 0 0 3349 d15 net/core/filter_pre.o on x86_64 : # size net/core/filter.o net/core/filter_pre.o text data bss dec hex filename 5173 0 0 5173 1435 net/core/filter.o 5224 0 0 5224 1468 net/core/filter_pre.o Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
0302b8622ce696af1cda22fcf207d3793350e896	18-Nov-2010	Randy Dunlap <randy.dunlap@oracle.com>	net: fix kernel-doc for sk_filter_rcu_release Fix kernel-doc warning for sk_filter_rcu_release(): Warning(net/core/filter.c:586): missing initial short description on line: * sk_filter_rcu_release: Release a socket filter by rcu_head Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller <davem@davemloft.net>
4c3710afbc333c33100739dec10662b4ee64e219	16-Nov-2010	Changli Gao <xiaosuo@gmail.com>	net: move definitions of BPF_S_* to net/core/filter.c BPF_S_* are used internally, should not be exposed to the others. Signed-off-by: Changli Gao <xiaosuo@gmail.com> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: David S. Miller <davem@davemloft.net>
cba328fc5ede9091616e7296483840869b615a46	16-Nov-2010	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>	filter: Optimize instruction revalidation code. Since repeating u16 value to u8 value conversion using switch() clause's case statement is wasteful, this patch introduces u16 to u8 mapping table and removes most of case statements. As a result, the size of net/core/filter.o is reduced by about 29% on x86. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
57fe93b374a6b8711995c2d466c502af9f3a08bb	10-Nov-2010	David S. Miller <davem@davemloft.net>	filter: make sure filters dont read uninitialized memory There is a possibility malicious users can get limited information about uninitialized stack mem array. Even if sk_run_filter() result is bound to packet length (0 .. 65535), we could imagine this can be used by hostile user. Initializing mem[] array, like Dan Rosenberg suggested in his patch is expensive since most filters dont even use this array. Its hard to make the filter validation in sk_chk_filter(), because of the jumps. This might be done later. In this patch, I use a bitmap (a single long var) so that only filters using mem[] loads/stores pay the price of added security checks. For other filters, additional cost is a single instruction. [ Since we access fentry->k a lot now, cache it in a local variable and mark filter entry pointer as const. -DaveM ] Reported-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
0d7da9ddd9a4eb7808698d04b98bf9d62d02649b	25-Oct-2010	Eric Dumazet <eric.dumazet@gmail.com>	net: add __rcu annotation to sk_filter Add __rcu annotation to : (struct sock)->sk_filter And use appropriate rcu primitives to reduce sparse warnings if CONFIG_SPARSE_RCU_POINTER=y Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
f91ff5b9ff529be8aac2039af63b2c8ea6cd6ebe	27-Sep-2010	Eric Dumazet <eric.dumazet@gmail.com>	net: sk_{detach\|attach}_filter() rcu fixes sk_attach_filter() and sk_detach_filter() are run with socket locked. Use the appropriate rcu_dereference_protected() instead of blocking BH, and rcu_dereference_bh(). There is no point adding BH prevention and memory barrier. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
01f2f3f6ef4d076c0c10a8a7b42624416d56b523	19-Jun-2010	Hagen Paul Pfeifer <hagen@jauu.net>	net: optimize Berkeley Packet Filter (BPF) processing Gcc is currenlty not in the ability to optimize the switch statement in sk_run_filter() because of dense case labels. This patch replace the OR'd labels with ordered sequenced case labels. The sk_chk_filter() function is modified to patch/replace the original OPCODES in a ordered but equivalent form. gcc is now in the ability to transform the switch statement in sk_run_filter into a jump table of complexity O(1). Until this patch gcc generates a sequence of conditional branches (O(n) of 567 byte .text segment size (arch x86_64): 7ff: 8b 06 mov (%rsi),%eax 801: 66 83 f8 35 cmp $0x35,%ax 805: 0f 84 d0 02 00 00 je adb <sk_run_filter+0x31d> 80b: 0f 87 07 01 00 00 ja 918 <sk_run_filter+0x15a> 811: 66 83 f8 15 cmp $0x15,%ax 815: 0f 84 c5 02 00 00 je ae0 <sk_run_filter+0x322> 81b: 77 73 ja 890 <sk_run_filter+0xd2> 81d: 66 83 f8 04 cmp $0x4,%ax 821: 0f 84 17 02 00 00 je a3e <sk_run_filter+0x280> 827: 77 29 ja 852 <sk_run_filter+0x94> 829: 66 83 f8 01 cmp $0x1,%ax [...] With the modification the compiler translate the switch statement into the following jump table fragment: 7ff: 66 83 3e 2c cmpw $0x2c,(%rsi) 803: 0f 87 1f 02 00 00 ja a28 <sk_run_filter+0x26a> 809: 0f b7 06 movzwl (%rsi),%eax 80c: ff 24 c5 00 00 00 00 jmpq *0x0(,%rax,8) 813: 44 89 e3 mov %r12d,%ebx 816: e9 43 03 00 00 jmpq b5e <sk_run_filter+0x3a0> 81b: 41 89 dc mov %ebx,%r12d 81e: e9 3b 03 00 00 jmpq b5e <sk_run_filter+0x3a0> Furthermore, I reordered the instructions to reduce cache line misses by order the most common instruction to the start. Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: David S. Miller <davem@davemloft.net>