diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/net/phy.txt | 1 | ||||
| -rw-r--r-- | Documentation/networking/filter.txt | 608 | ||||
| -rw-r--r-- | Documentation/networking/ip-sysctl.txt | 10 | ||||
| -rw-r--r-- | Documentation/networking/packet_mmap.txt | 21 | ||||
| -rw-r--r-- | Documentation/networking/phy.txt | 3 | ||||
| -rw-r--r-- | Documentation/networking/regulatory.txt | 4 | ||||
| -rw-r--r-- | Documentation/networking/timestamping.txt | 9 | ||||
| -rw-r--r-- | Documentation/networking/timestamping/.gitignore | 1 | ||||
| -rw-r--r-- | Documentation/networking/timestamping/Makefile | 5 | ||||
| -rw-r--r-- | Documentation/networking/timestamping/hwtstamp_config.c | 134 | ||||
| -rw-r--r-- | Documentation/unaligned-memory-access.txt | 28 |
11 files changed, 761 insertions, 63 deletions
diff --git a/Documentation/devicetree/bindings/net/phy.txt b/Documentation/devicetree/bindings/net/phy.txt index 7cd18fbfcf7..f648094abc3 100644 --- a/Documentation/devicetree/bindings/net/phy.txt +++ b/Documentation/devicetree/bindings/net/phy.txt @@ -22,6 +22,7 @@ Optional Properties: specifications. If neither of these are specified, the default is to assume clause 22. The compatible list may also contain other elements. +- max-speed: Maximum PHY supported speed (10, 100, 1000...) Example: diff --git a/Documentation/networking/filter.txt b/Documentation/networking/filter.txt index cdb3e40b9d1..a06b48d2f5c 100644 --- a/Documentation/networking/filter.txt +++ b/Documentation/networking/filter.txt @@ -1,49 +1,563 @@ -filter.txt: Linux Socket Filtering -Written by: Jay Schulist <jschlst@samba.org> +Linux Socket Filtering aka Berkeley Packet Filter (BPF) +======================================================= Introduction -============ - - Linux Socket Filtering is derived from the Berkeley -Packet Filter. There are some distinct differences between -the BSD and Linux Kernel Filtering. - -Linux Socket Filtering (LSF) allows a user-space program to -attach a filter onto any socket and allow or disallow certain -types of data to come through the socket. LSF follows exactly -the same filter code structure as the BSD Berkeley Packet Filter -(BPF), so referring to the BSD bpf.4 manpage is very helpful in -creating filters. - -LSF is much simpler than BPF. One does not have to worry about -devices or anything like that. You simply create your filter -code, send it to the kernel via the SO_ATTACH_FILTER option and -if your filter code passes the kernel check on it, you then -immediately begin filtering data on that socket. - -You can also detach filters from your socket via the -SO_DETACH_FILTER option. This will probably not be used much -since when you close a socket that has a filter on it the -filter is automagically removed. The other less common case -may be adding a different filter on the same socket where you had another -filter that is still running: the kernel takes care of removing -the old one and placing your new one in its place, assuming your -filter has passed the checks, otherwise if it fails the old filter -will remain on that socket. - -SO_LOCK_FILTER option allows to lock the filter attached to a -socket. Once set, a filter cannot be removed or changed. This allows -one process to setup a socket, attach a filter, lock it then drop -privileges and be assured that the filter will be kept until the -socket is closed. - -Examples -======== - -Ioctls- -setsockopt(sockfd, SOL_SOCKET, SO_ATTACH_FILTER, &Filter, sizeof(Filter)); -setsockopt(sockfd, SOL_SOCKET, SO_DETACH_FILTER, &value, sizeof(value)); -setsockopt(sockfd, SOL_SOCKET, SO_LOCK_FILTER, &value, sizeof(value)); - -See the BSD bpf.4 manpage and the BSD Packet Filter paper written by -Steven McCanne and Van Jacobson of Lawrence Berkeley Laboratory. +------------ + +Linux Socket Filtering (LSF) is derived from the Berkeley Packet Filter. +Though there are some distinct differences between the BSD and Linux +Kernel filtering, but when we speak of BPF or LSF in Linux context, we +mean the very same mechanism of filtering in the Linux kernel. + +BPF allows a user-space program to attach a filter onto any socket and +allow or disallow certain types of data to come through the socket. LSF +follows exactly the same filter code structure as BSD's BPF, so referring +to the BSD bpf.4 manpage is very helpful in creating filters. + +On Linux, BPF is much simpler than on BSD. One does not have to worry +about devices or anything like that. You simply create your filter code, +send it to the kernel via the SO_ATTACH_FILTER option and if your filter +code passes the kernel check on it, you then immediately begin filtering +data on that socket. + +You can also detach filters from your socket via the SO_DETACH_FILTER +option. This will probably not be used much since when you close a socket +that has a filter on it the filter is automagically removed. The other +less common case may be adding a different filter on the same socket where +you had another filter that is still running: the kernel takes care of +removing the old one and placing your new one in its place, assuming your +filter has passed the checks, otherwise if it fails the old filter will +remain on that socket. + +SO_LOCK_FILTER option allows to lock the filter attached to a socket. Once +set, a filter cannot be removed or changed. This allows one process to +setup a socket, attach a filter, lock it then drop privileges and be +assured that the filter will be kept until the socket is closed. + +The biggest user of this construct might be libpcap. Issuing a high-level +filter command like `tcpdump -i em1 port 22` passes through the libpcap +internal compiler that generates a structure that can eventually be loaded +via SO_ATTACH_FILTER to the kernel. `tcpdump -i em1 port 22 -ddd` +displays what is being placed into this structure. + +Although we were only speaking about sockets here, BPF in Linux is used +in many more places. There's xt_bpf for netfilter, cls_bpf in the kernel +qdisc layer, SECCOMP-BPF (SECure COMPuting [1]), and lots of other places +such as team driver, PTP code, etc where BPF is being used. + + [1] Documentation/prctl/seccomp_filter.txt + +Original BPF paper: + +Steven McCanne and Van Jacobson. 1993. The BSD packet filter: a new +architecture for user-level packet capture. In Proceedings of the +USENIX Winter 1993 Conference Proceedings on USENIX Winter 1993 +Conference Proceedings (USENIX'93). USENIX Association, Berkeley, +CA, USA, 2-2. [http://www.tcpdump.org/papers/bpf-usenix93.pdf] + +Structure +--------- + +User space applications include <linux/filter.h> which contains the +following relevant structures: + +struct sock_filter { /* Filter block */ + __u16 code; /* Actual filter code */ + __u8 jt; /* Jump true */ + __u8 jf; /* Jump false */ + __u32 k; /* Generic multiuse field */ +}; + +Such a structure is assembled as an array of 4-tuples, that contains +a code, jt, jf and k value. jt and jf are jump offsets and k a generic +value to be used for a provided code. + +struct sock_fprog { /* Required for SO_ATTACH_FILTER. */ + unsigned short len; /* Number of filter blocks */ + struct sock_filter __user *filter; +}; + +For socket filtering, a pointer to this structure (as shown in +follow-up example) is being passed to the kernel through setsockopt(2). + +Example +------- + +#include <sys/socket.h> +#include <sys/types.h> +#include <arpa/inet.h> +#include <linux/if_ether.h> +/* ... */ + +/* From the example above: tcpdump -i em1 port 22 -dd */ +struct sock_filter code[] = { + { 0x28, 0, 0, 0x0000000c }, + { 0x15, 0, 8, 0x000086dd }, + { 0x30, 0, 0, 0x00000014 }, + { 0x15, 2, 0, 0x00000084 }, + { 0x15, 1, 0, 0x00000006 }, + { 0x15, 0, 17, 0x00000011 }, + { 0x28, 0, 0, 0x00000036 }, + { 0x15, 14, 0, 0x00000016 }, + { 0x28, 0, 0, 0x00000038 }, + { 0x15, 12, 13, 0x00000016 }, + { 0x15, 0, 12, 0x00000800 }, + { 0x30, 0, 0, 0x00000017 }, + { 0x15, 2, 0, 0x00000084 }, + { 0x15, 1, 0, 0x00000006 }, + { 0x15, 0, 8, 0x00000011 }, + { 0x28, 0, 0, 0x00000014 }, + { 0x45, 6, 0, 0x00001fff }, + { 0xb1, 0, 0, 0x0000000e }, + { 0x48, 0, 0, 0x0000000e }, + { 0x15, 2, 0, 0x00000016 }, + { 0x48, 0, 0, 0x00000010 }, + { 0x15, 0, 1, 0x00000016 }, + { 0x06, 0, 0, 0x0000ffff }, + { 0x06, 0, 0, 0x00000000 }, +}; + +struct sock_fprog bpf = { + .len = ARRAY_SIZE(code), + .filter = code, +}; + +sock = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); +if (sock < 0) + /* ... bail out ... */ + +ret = setsockopt(sock, SOL_SOCKET, SO_ATTACH_FILTER, &bpf, sizeof(bpf)); +if (ret < 0) + /* ... bail out ... */ + +/* ... */ +close(sock); + +The above example code attaches a socket filter for a PF_PACKET socket +in order to let all IPv4/IPv6 packets with port 22 pass. The rest will +be dropped for this socket. + +The setsockopt(2) call to SO_DETACH_FILTER doesn't need any arguments +and SO_LOCK_FILTER for preventing the filter to be detached, takes an +integer value with 0 or 1. + +Note that socket filters are not restricted to PF_PACKET sockets only, +but can also be used on other socket families. + +Summary of system calls: + + * setsockopt(sockfd, SOL_SOCKET, SO_ATTACH_FILTER, &val, sizeof(val)); + * setsockopt(sockfd, SOL_SOCKET, SO_DETACH_FILTER, &val, sizeof(val)); + * setsockopt(sockfd, SOL_SOCKET, SO_LOCK_FILTER, &val, sizeof(val)); + +Normally, most use cases for socket filtering on packet sockets will be +covered by libpcap in high-level syntax, so as an application developer +you should stick to that. libpcap wraps its own layer around all that. + +Unless i) using/linking to libpcap is not an option, ii) the required BPF +filters use Linux extensions that are not supported by libpcap's compiler, +iii) a filter might be more complex and not cleanly implementable with +libpcap's compiler, or iv) particular filter codes should be optimized +differently than libpcap's internal compiler does; then in such cases +writing such a filter "by hand" can be of an alternative. For example, +xt_bpf and cls_bpf users might have requirements that could result in +more complex filter code, or one that cannot be expressed with libpcap +(e.g. different return codes for various code paths). Moreover, BPF JIT +implementors may wish to manually write test cases and thus need low-level +access to BPF code as well. + +BPF engine and instruction set +------------------------------ + +Under tools/net/ there's a small helper tool called bpf_asm which can +be used to write low-level filters for example scenarios mentioned in the +previous section. Asm-like syntax mentioned here has been implemented in +bpf_asm and will be used for further explanations (instead of dealing with +less readable opcodes directly, principles are the same). The syntax is +closely modelled after Steven McCanne's and Van Jacobson's BPF paper. + +The BPF architecture consists of the following basic elements: + + Element Description + + A 32 bit wide accumulator + X 32 bit wide X register + M[] 16 x 32 bit wide misc registers aka "scratch memory + store", addressable from 0 to 15 + +A program, that is translated by bpf_asm into "opcodes" is an array that +consists of the following elements (as already mentioned): + + op:16, jt:8, jf:8, k:32 + +The element op is a 16 bit wide opcode that has a particular instruction +encoded. jt and jf are two 8 bit wide jump targets, one for condition +"jump if true", the other one "jump if false". Eventually, element k +contains a miscellaneous argument that can be interpreted in different +ways depending on the given instruction in op. + +The instruction set consists of load, store, branch, alu, miscellaneous +and return instructions that are also represented in bpf_asm syntax. This +table lists all bpf_asm instructions available resp. what their underlying +opcodes as defined in linux/filter.h stand for: + + Instruction Addressing mode Description + + ld 1, 2, 3, 4, 10 Load word into A + ldi 4 Load word into A + ldh 1, 2 Load half-word into A + ldb 1, 2 Load byte into A + ldx 3, 4, 5, 10 Load word into X + ldxi 4 Load word into X + ldxb 5 Load byte into X + + st 3 Store A into M[] + stx 3 Store X into M[] + + jmp 6 Jump to label + ja 6 Jump to label + jeq 7, 8 Jump on k == A + jneq 8 Jump on k != A + jne 8 Jump on k != A + jlt 8 Jump on k < A + jle 8 Jump on k <= A + jgt 7, 8 Jump on k > A + jge 7, 8 Jump on k >= A + jset 7, 8 Jump on k & A + + add 0, 4 A + <x> + sub 0, 4 A - <x> + mul 0, 4 A * <x> + div 0, 4 A / <x> + mod 0, 4 A % <x> + neg 0, 4 !A + and 0, 4 A & <x> + or 0, 4 A | <x> + xor 0, 4 A ^ <x> + lsh 0, 4 A << <x> + rsh 0, 4 A >> <x> + + tax Copy A into X + txa Copy X into A + + ret 4, 9 Return + +The next table shows addressing formats from the 2nd column: + + Addressing mode Syntax Description + + 0 x/%x Register X + 1 [k] BHW at byte offset k in the packet + 2 [x + k] BHW at the offset X + k in the packet + 3 M[k] Word at offset k in M[] + 4 #k Literal value stored in k + 5 4*([k]&0xf) Lower nibble * 4 at byte offset k in the packet + 6 L Jump label L + 7 #k,Lt,Lf Jump to Lt if true, otherwise jump to Lf + 8 #k,Lt Jump to Lt if predicate is true + 9 a/%a Accumulator A + 10 extension BPF extension + +The Linux kernel also has a couple of BPF extensions that are used along +with the class of load instructions by "overloading" the k argument with +a negative offset + a particular extension offset. The result of such BPF +extensions are loaded into A. + +Possible BPF extensions are shown in the following table: + + Extension Description + + len skb->len + proto skb->protocol + type skb->pkt_type + poff Payload start offset + ifidx skb->dev->ifindex + nla Netlink attribute of type X with offset A + nlan Nested Netlink attribute of type X with offset A + mark skb->mark + queue skb->queue_mapping + hatype skb->dev->type + rxhash skb->rxhash + cpu raw_smp_processor_id() + vlan_tci vlan_tx_tag_get(skb) + vlan_pr vlan_tx_tag_present(skb) + +These extensions can also be prefixed with '#'. +Examples for low-level BPF: + +** ARP packets: + + ldh [12] + jne #0x806, drop + ret #-1 + drop: ret #0 + +** IPv4 TCP packets: + + ldh [12] + jne #0x800, drop + ldb [23] + jneq #6, drop + ret #-1 + drop: ret #0 + +** (Accelerated) VLAN w/ id 10: + + ld vlan_tci + jneq #10, drop + ret #-1 + drop: ret #0 + +** SECCOMP filter example: + + ld [4] /* offsetof(struct seccomp_data, arch) */ + jne #0xc000003e, bad /* AUDIT_ARCH_X86_64 */ + ld [0] /* offsetof(struct seccomp_data, nr) */ + jeq #15, good /* __NR_rt_sigreturn */ + jeq #231, good /* __NR_exit_group */ + jeq #60, good /* __NR_exit */ + jeq #0, good /* __NR_read */ + jeq #1, good /* __NR_write */ + jeq #5, good /* __NR_fstat */ + jeq #9, good /* __NR_mmap */ + jeq #14, good /* __NR_rt_sigprocmask */ + jeq #13, good /* __NR_rt_sigaction */ + jeq #35, good /* __NR_nanosleep */ + bad: ret #0 /* SECCOMP_RET_KILL */ + good: ret #0x7fff0000 /* SECCOMP_RET_ALLOW */ + +The above example code can be placed into a file (here called "foo"), and +then be passed to the bpf_asm tool for generating opcodes, output that xt_bpf +and cls_bpf understands and can directly be loaded with. Example with above +ARP code: + +$ ./bpf_asm foo +4,40 0 0 12,21 0 1 2054,6 0 0 4294967295,6 0 0 0, + +In copy and paste C-like output: + +$ ./bpf_asm -c foo +{ 0x28, 0, 0, 0x0000000c }, +{ 0x15, 0, 1, 0x00000806 }, +{ 0x06, 0, 0, 0xffffffff }, +{ 0x06, 0, 0, 0000000000 }, + +In particular, as usage with xt_bpf or cls_bpf can result in more complex BPF +filters that might not be obvious at first, it's good to test filters before +attaching to a live system. For that purpose, there's a small tool called +bpf_dbg under tools/net/ in the kernel source directory. This debugger allows +for testing BPF filters against given pcap files, single stepping through the +BPF code on the pcap's packets and to do BPF machine register dumps. + +Starting bpf_dbg is trivial and just requires issuing: + +# ./bpf_dbg + +In case input and output do not equal stdin/stdout, bpf_dbg takes an +alternative stdin source as a first argument, and an alternative stdout +sink as a second one, e.g. `./bpf_dbg test_in.txt test_out.txt`. + +Other than that, a particular libreadline configuration can be set via +file "~/.bpf_dbg_init" and the command history is stored in the file +"~/.bpf_dbg_history". + +Interaction in bpf_dbg happens through a shell that also has auto-completion +support (follow-up example commands starting with '>' denote bpf_dbg shell). +The usual workflow would be to ... + +> load bpf 6,40 0 0 12,21 0 3 2048,48 0 0 23,21 0 1 1,6 0 0 65535,6 0 0 0 + Loads a BPF filter from standard output of bpf_asm, or transformed via + e.g. `tcpdump -iem1 -ddd port 22 | tr '\n' ','`. Note that for JIT + debugging (next section), this command creates a temporary socket and + loads the BPF code into the kernel. Thus, this will also be useful for + JIT developers. + +> load pcap foo.pcap + Loads standard tcpdump pcap file. + +> run [<n>] +bpf passes:1 fails:9 + Runs through all packets from a pcap to account how many passes and fails + the filter will generate. A limit of packets to traverse can be given. + +> disassemble +l0: ldh [12] +l1: jeq #0x800, l2, l5 +l2: ldb [23] +l3: jeq #0x1, l4, l5 +l4: ret #0xffff +l5: ret #0 + Prints out BPF code disassembly. + +> dump +/* { op, jt, jf, k }, */ +{ 0x28, 0, 0, 0x0000000c }, +{ 0x15, 0, 3, 0x00000800 }, +{ 0x30, 0, 0, 0x00000017 }, +{ 0x15, 0, 1, 0x00000001 }, +{ 0x06, 0, 0, 0x0000ffff }, +{ 0x06, 0, 0, 0000000000 }, + Prints out C-style BPF code dump. + +> breakpoint 0 +breakpoint at: l0: ldh [12] +> breakpoint 1 +breakpoint at: l1: jeq #0x800, l2, l5 + ... + Sets breakpoints at particular BPF instructions. Issuing a `run` command + will walk through the pcap file continuing from the current packet and + break when a breakpoint is being hit (another `run` will continue from + the currently active breakpoint executing next instructions): + + > run + -- register dump -- + pc: [0] <-- program counter + code: [40] jt[0] jf[0] k[12] <-- plain BPF code of current instruction + curr: l0: ldh [12] <-- disassembly of current instruction + A: [00000000][0] <-- content of A (hex, decimal) + X: [00000000][0] <-- content of X (hex, decimal) + M[0,15]: [00000000][0] <-- folded content of M (hex, decimal) + -- packet dump -- <-- Current packet from pcap (hex) + len: 42 + 0: 00 19 cb 55 55 a4 00 14 a4 43 78 69 08 06 00 01 + 16: 08 00 06 04 00 01 00 14 a4 43 78 69 0a 3b 01 26 + 32: 00 00 00 00 00 00 0a 3b 01 01 + (breakpoint) + > + +> breakpoint +breakpoints: 0 1 + Prints currently set breakpoints. + +> step [-<n>, +<n>] + Performs single stepping through the BPF program from the current pc + offset. Thus, on each step invocation, above register dump is issued. + This can go forwards and backwards in time, a plain `step` will break + on the next BPF instruction, thus +1. (No `run` needs to be issued here.) + +> select <n> + Selects a given packet from the pcap file to continue from. Thus, on + the next `run` or `step`, the BPF program is being evaluated against + the user pre-selected packet. Numbering starts just as in Wireshark + with index 1. + +> quit +# + Exits bpf_dbg. + +JIT compiler +------------ + +The Linux kernel has a built-in BPF JIT compiler for x86_64, SPARC, PowerPC, +ARM and s390 and can be enabled through CONFIG_BPF_JIT. The JIT compiler is +transparently invoked for each attached filter from user space or for internal +kernel users if it has been previously enabled by root: + + echo 1 > /proc/sys/net/core/bpf_jit_enable + +For JIT developers, doing audits etc, each compile run can output the generated +opcode image into the kernel log via: + + echo 2 > /proc/sys/net/core/bpf_jit_enable + +Example output from dmesg: + +[ 3389.935842] flen=6 proglen=70 pass=3 image=ffffffffa0069c8f +[ 3389.935847] JIT code: 00000000: 55 48 89 e5 48 83 ec 60 48 89 5d f8 44 8b 4f 68 +[ 3389.935849] JIT code: 00000010: 44 2b 4f 6c 4c 8b 87 d8 00 00 00 be 0c 00 00 00 +[ 3389.935850] JIT code: 00000020: e8 1d 94 ff e0 3d 00 08 00 00 75 16 be 17 00 00 +[ 3389.935851] JIT code: 00000030: 00 e8 28 94 ff e0 83 f8 01 75 07 b8 ff ff 00 00 +[ 3389.935852] JIT code: 00000040: eb 02 31 c0 c9 c3 + +In the kernel source tree under tools/net/, there's bpf_jit_disasm for +generating disassembly out of the kernel log's hexdump: + +# ./bpf_jit_disasm +70 bytes emitted from JIT compiler (pass:3, flen:6) +ffffffffa0069c8f + <x>: + 0: push %rbp + 1: mov %rsp,%rbp + 4: sub $0x60,%rsp + 8: mov %rbx,-0x8(%rbp) + c: mov 0x68(%rdi),%r9d + 10: sub 0x6c(%rdi),%r9d + 14: mov 0xd8(%rdi),%r8 + 1b: mov $0xc,%esi + 20: callq 0xffffffffe0ff9442 + 25: cmp $0x800,%eax + 2a: jne 0x0000000000000042 + 2c: mov $0x17,%esi + 31: callq 0xffffffffe0ff945e + 36: cmp $0x1,%eax + 39: jne 0x0000000000000042 + 3b: mov $0xffff,%eax + 40: jmp 0x0000000000000044 + 42: xor %eax,%eax + 44: leaveq + 45: retq + +Issuing option `-o` will "annotate" opcodes to resulting assembler +instructions, which can be very useful for JIT developers: + +# ./bpf_jit_disasm -o +70 bytes emitted from JIT compiler (pass:3, flen:6) +ffffffffa0069c8f + <x>: + 0: push %rbp + 55 + 1: mov %rsp,%rbp + 48 89 e5 + 4: sub $0x60,%rsp + 48 83 ec 60 + 8: mov %rbx,-0x8(%rbp) + 48 89 5d f8 + c: mov 0x68(%rdi),%r9d + 44 8b 4f 68 + 10: sub 0x6c(%rdi),%r9d + 44 2b 4f 6c + 14: mov 0xd8(%rdi),%r8 + 4c 8b 87 d8 00 00 00 + 1b: mov $0xc,%esi + be 0c 00 00 00 + 20: callq 0xffffffffe0ff9442 + e8 1d 94 ff e0 + 25: cmp $0x800,%eax + 3d 00 08 00 00 + 2a: jne 0x0000000000000042 + 75 16 + 2c: mov $0x17,%esi + be 17 00 00 00 + 31: callq 0xffffffffe0ff945e + e8 28 94 ff e0 + 36: cmp $0x1,%eax + 83 f8 01 + 39: jne 0x0000000000000042 + 75 07 + 3b: mov $0xffff,%eax + b8 ff ff 00 00 + 40: jmp 0x0000000000000044 + eb 02 + 42: xor %eax,%eax + 31 c0 + 44: leaveq + c9 + 45: retq + c3 + +For BPF JIT developers, bpf_jit_disasm, bpf_asm and bpf_dbg provides a useful +toolchain for developing and testing the kernel's JIT compiler. + +Misc +---- + +Also trinity, the Linux syscall fuzzer, has built-in support for BPF and +SECCOMP-BPF kernel fuzzing. + +Written by +---------- + +The document was written in the hope that it is found useful and in order +to give potential BPF hackers or security auditors a better overview of +the underlying architecture. + +Jay Schulist <jschlst@samba.org> +Daniel Borkmann <dborkman@redhat.com> diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index 8a984e994e6..f76d177895d 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -160,6 +160,16 @@ tcp_app_win - INTEGER buffer. Value 0 is special, it means that nothing is reserved. Default: 31 +tcp_autocorking - BOOLEAN + Enable TCP auto corking : + When applications do consecutive small write()/sendmsg() system calls, + we try to coalesce these small writes as much as possible, to lower + total amount of sent packets. This is done if at least one prior + packet for the flow is waiting in Qdisc queues or device transmit + queue. Applications can still use TCP_CORK for optimal behavior + when they know how/when to uncork their sockets. + Default : 1 + tcp_available_congestion_control - STRING Shows the available congestion control choices that are registered. More congestion control algorithms may be available as modules, diff --git a/Documentation/networking/packet_mmap.txt b/Documentation/networking/packet_mmap.txt index 8e48e3b1422..4288ffafba9 100644 --- a/Documentation/networking/packet_mmap.txt +++ b/Documentation/networking/packet_mmap.txt @@ -953,6 +953,27 @@ int main(int argc, char **argp) } ------------------------------------------------------------------------------- ++ PACKET_QDISC_BYPASS +------------------------------------------------------------------------------- + +If there is a requirement to load the network with many packets in a similar +fashion as pktgen does, you might set the following option after socket +creation: + + int one = 1; + setsockopt(fd, SOL_PACKET, PACKET_QDISC_BYPASS, &one, sizeof(one)); + +This has the side-effect, that packets sent through PF_PACKET will bypass the +kernel's qdisc layer and are forcedly pushed to the driver directly. Meaning, +packet are not buffered, tc disciplines are ignored, increased loss can occur +and such packets are also not visible to other PF_PACKET sockets anymore. So, +you have been warned; generally, this can be useful for stress testing various +components of a system. + +On default, PACKET_QDISC_BYPASS is disabled and needs to be explicitly enabled +on PF_PACKET sockets. + +------------------------------------------------------------------------------- + PACKET_TIMESTAMP ------------------------------------------------------------------------------- diff --git a/Documentation/networking/phy.txt b/Documentation/networking/phy.txt index d5b1a393524..ebf27071940 100644 --- a/Documentation/networking/phy.txt +++ b/Documentation/networking/phy.txt @@ -255,7 +255,8 @@ Writing a PHY driver config_init: configures PHY into a sane state after a reset. For instance, a Davicom PHY requires descrambling disabled. - probe: Does any setup needed by the driver + probe: Allocate phy->priv, optionally refuse to bind. + PHY may not have been reset or had fixups run yet. suspend/resume: power management config_aneg: Changes the speed/duplex/negotiation settings read_status: Reads the current speed/duplex/negotiation settings diff --git a/Documentation/networking/regulatory.txt b/Documentation/networking/regulatory.txt index 9551622d0a7..356f791af57 100644 --- a/Documentation/networking/regulatory.txt +++ b/Documentation/networking/regulatory.txt @@ -159,10 +159,10 @@ struct ieee80211_regdomain mydriver_jp_regdom = { REG_RULE(2412-20, 2484+20, 40, 6, 20, 0), /* IEEE 802.11a, channels 34..48 */ REG_RULE(5170-20, 5240+20, 40, 6, 20, - NL80211_RRF_PASSIVE_SCAN), + NL80211_RRF_NO_IR), /* IEEE 802.11a, channels 52..64 */ REG_RULE(5260-20, 5320+20, 40, 6, 20, - NL80211_RRF_NO_IBSS | + NL80211_RRF_NO_IR| NL80211_RRF_DFS), } }; diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt index 98097d8cb91..661d3c316a1 100644 --- a/Documentation/networking/timestamping.txt +++ b/Documentation/networking/timestamping.txt @@ -85,7 +85,7 @@ Filled in if SOF_TIMESTAMPING_SYS_HARDWARE is set. Requires support by the network device and will be empty without that support. -SIOCSHWTSTAMP: +SIOCSHWTSTAMP, SIOCGHWTSTAMP: Hardware time stamping must also be initialized for each device driver that is expected to do hardware time stamping. The parameter is defined in @@ -115,6 +115,10 @@ Only a processes with admin rights may change the configuration. User space is responsible to ensure that multiple processes don't interfere with each other and that the settings are reset. +Any process can read the actual configuration by passing this +structure to ioctl(SIOCGHWTSTAMP) in the same way. However, this has +not been implemented in all drivers. + /* possible values for hwtstamp_config->tx_type */ enum { /* @@ -157,7 +161,8 @@ DEVICE IMPLEMENTATION A driver which supports hardware time stamping must support the SIOCSHWTSTAMP ioctl and update the supplied struct hwtstamp_config with -the actual values as described in the section on SIOCSHWTSTAMP. +the actual values as described in the section on SIOCSHWTSTAMP. It +should also support SIOCGHWTSTAMP. Time stamps for received packets must be stored in the skb. To get a pointer to the shared time stamp structure of the skb call skb_hwtstamps(). Then diff --git a/Documentation/networking/timestamping/.gitignore b/Documentation/networking/timestamping/.gitignore index 71e81eb2e22..a380159765c 100644 --- a/Documentation/networking/timestamping/.gitignore +++ b/Documentation/networking/timestamping/.gitignore @@ -1 +1,2 @@ timestamping +hwtstamp_config diff --git a/Documentation/networking/timestamping/Makefile b/Documentation/networking/timestamping/Makefile index e79973443e9..d934afc8306 100644 --- a/Documentation/networking/timestamping/Makefile +++ b/Documentation/networking/timestamping/Makefile @@ -2,12 +2,13 @@ obj- := dummy.o # List of programs to build -hostprogs-y := timestamping +hostprogs-y := timestamping hwtstamp_config # Tell kbuild to always build the programs always := $(hostprogs-y) HOSTCFLAGS_timestamping.o += -I$(objtree)/usr/include +HOSTCFLAGS_hwtstamp_config.o += -I$(objtree)/usr/include clean: - rm -f timestamping + rm -f timestamping hwtstamp_config diff --git a/Documentation/networking/timestamping/hwtstamp_config.c b/Documentation/networking/timestamping/hwtstamp_config.c new file mode 100644 index 00000000000..e8b685a7f15 --- /dev/null +++ b/Documentation/networking/timestamping/hwtstamp_config.c @@ -0,0 +1,134 @@ +/* Test program for SIOC{G,S}HWTSTAMP + * Copyright 2013 Solarflare Communications + * Author: Ben Hutchings + */ + +#include <errno.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include <sys/socket.h> +#include <sys/ioctl.h> + +#include <linux/if.h> +#include <linux/net_tstamp.h> +#include <linux/sockios.h> + +static int +lookup_value(const char **names, int size, const char *name) +{ + int value; + + for (value = 0; value < size; value++) + if (names[value] && strcasecmp(names[value], name) == 0) + return value; + + return -1; +} + +static const char * +lookup_name(const char **names, int size, int value) +{ + return (value >= 0 && value < size) ? names[value] : NULL; +} + +static void list_names(FILE *f, const char **names, int size) +{ + int value; + + for (value = 0; value < size; value++) + if (names[value]) + fprintf(f, " %s\n", names[value]); +} + +static const char *tx_types[] = { +#define TX_TYPE(name) [HWTSTAMP_TX_ ## name] = #name + TX_TYPE(OFF), + TX_TYPE(ON), + TX_TYPE(ONESTEP_SYNC) +#undef TX_TYPE +}; +#define N_TX_TYPES ((int)(sizeof(tx_types) / sizeof(tx_types[0]))) + +static const char *rx_filters[] = { +#define RX_FILTER(name) [HWTSTAMP_FILTER_ ## name] = #name + RX_FILTER(NONE), + RX_FILTER(ALL), + RX_FILTER(SOME), + RX_FILTER(PTP_V1_L4_EVENT), + RX_FILTER(PTP_V1_L4_SYNC), + RX_FILTER(PTP_V1_L4_DELAY_REQ), + RX_FILTER(PTP_V2_L4_EVENT), + RX_FILTER(PTP_V2_L4_SYNC), + RX_FILTER(PTP_V2_L4_DELAY_REQ), + RX_FILTER(PTP_V2_L2_EVENT), + RX_FILTER(PTP_V2_L2_SYNC), + RX_FILTER(PTP_V2_L2_DELAY_REQ), + RX_FILTER(PTP_V2_EVENT), + RX_FILTER(PTP_V2_SYNC), + RX_FILTER(PTP_V2_DELAY_REQ), +#undef RX_FILTER +}; +#define N_RX_FILTERS ((int)(sizeof(rx_filters) / sizeof(rx_filters[0]))) + +static void usage(void) +{ + fputs("Usage: hwtstamp_config if_name [tx_type rx_filter]\n" + "tx_type is any of (case-insensitive):\n", + stderr); + list_names(stderr, tx_types, N_TX_TYPES); + fputs("rx_filter is any of (case-insensitive):\n", stderr); + list_names(stderr, rx_filters, N_RX_FILTERS); +} + +int main(int argc, char **argv) +{ + struct ifreq ifr; + struct hwtstamp_config config; + const char *name; + int sock; + + if ((argc != 2 && argc != 4) || (strlen(argv[1]) >= IFNAMSIZ)) { + usage(); + return 2; + } + + if (argc == 4) { + config.flags = 0; + config.tx_type = lookup_value(tx_types, N_TX_TYPES, argv[2]); + config.rx_filter = lookup_value(rx_filters, N_RX_FILTERS, argv[3]); + if (config.tx_type < 0 || config.rx_filter < 0) { + usage(); + return 2; + } + } + + sock = socket(AF_INET, SOCK_DGRAM, 0); + if (sock < 0) { + perror("socket"); + return 1; + } + + strcpy(ifr.ifr_name, argv[1]); + ifr.ifr_data = (caddr_t)&config; + + if (ioctl(sock, (argc == 2) ? SIOCGHWTSTAMP : SIOCSHWTSTAMP, &ifr)) { + perror("ioctl"); + return 1; + } + + printf("flags = %#x\n", config.flags); + name = lookup_name(tx_types, N_TX_TYPES, config.tx_type); + if (name) + printf("tx_type = %s\n", name); + else + printf("tx_type = %d\n", config.tx_type); + name = lookup_name(rx_filters, N_RX_FILTERS, config.rx_filter); + if (name) + printf("rx_filter = %s\n", name); + else + printf("rx_filter = %d\n", config.rx_filter); + + return 0; +} diff --git a/Documentation/unaligned-memory-access.txt b/Documentation/unaligned-memory-access.txt index f866c72291b..a445da098bc 100644 --- a/Documentation/unaligned-memory-access.txt +++ b/Documentation/unaligned-memory-access.txt @@ -137,24 +137,34 @@ Code that causes unaligned access ================================= With the above in mind, let's move onto a real life example of a function -that can cause an unaligned memory access. The following function adapted +that can cause an unaligned memory access. The following function taken from include/linux/etherdevice.h is an optimized routine to compare two ethernet MAC addresses for equality. -unsigned int compare_ether_addr(const u8 *addr1, const u8 *addr2) +bool ether_addr_equal(const u8 *addr1, const u8 *addr2) { - const u16 *a = (const u16 *) addr1; - const u16 *b = (const u16 *) addr2; +#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS + u32 fold = ((*(const u32 *)addr1) ^ (*(const u32 *)addr2)) | + ((*(const u16 *)(addr1 + 4)) ^ (*(const u16 *)(addr2 + 4))); + + return fold == 0; +#else + const u16 *a = (const u16 *)addr1; + const u16 *b = (const u16 *)addr2; return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | (a[2] ^ b[2])) != 0; +#endif } -In the above function, the reference to a[0] causes 2 bytes (16 bits) to -be read from memory starting at address addr1. Think about what would happen -if addr1 was an odd address such as 0x10003. (Hint: it'd be an unaligned -access.) +In the above function, when the hardware has efficient unaligned access +capability, there is no issue with this code. But when the hardware isn't +able to access memory on arbitrary boundaries, the reference to a[0] causes +2 bytes (16 bits) to be read from memory starting at address addr1. + +Think about what would happen if addr1 was an odd address such as 0x10003. +(Hint: it'd be an unaligned access.) Despite the potential unaligned access problems with the above function, it -is included in the kernel anyway but is understood to only work on +is included in the kernel anyway but is understood to only work normally on 16-bit-aligned addresses. It is up to the caller to ensure this alignment or not use this function at all. This alignment-unsafe function is still useful as it is a decent optimization for the cases when you can ensure alignment, |