kernel.git/tools/lib/bpf/xsk.c, branch linux-5.4.y

libbpf: Don't use kernel-side u32 type in xsk.c

2020-01-26T09:01:05Z

[ Upstream commit a566e35f1e8b4b3be1e96a804d1cca38b578167c ] u32 is a kernel-side typedef. User-space library is supposed to use __u32. This breaks Github's projection of libbpf. Do u32 -> __u32 fix. Fixes: 94ff9ebb49a5 ("libbpf: Fix compatibility for kernels without need_wakeup") Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Acked-by: Björn Töpel Cc: Magnus Karlsson Link: https://lore.kernel.org/bpf/20191029055953.2461336-1-andriin@fb.com Signed-off-by: Sasha Levin

libbpf: Fix compatibility for kernels without need_wakeup

2020-01-26T09:00:57Z

commit 94ff9ebb49a546b7f009ed840bafa235c96d4c4b upstream. When the need_wakeup flag was added to AF_XDP, the format of the XDP_MMAP_OFFSETS getsockopt was extended. Code was added to the kernel to take care of compatibility issues arrising from running applications using any of the two formats. However, libbpf was not extended to take care of the case when the application/libbpf uses the new format but the kernel only supports the old format. This patch adds support in libbpf for parsing the old format, before the need_wakeup flag was added, and emulating a set of static need_wakeup flags that will always work for the application. v2 -> v3: * Incorporated code improvements suggested by Jonathan Lemon v1 -> v2: * Rebased to bpf-next * Rewrote the code as the previous version made you blind Fixes: a4500432c2587cb2a ("libbpf: add support for need_wakeup flag in AF_XDP part") Reported-by: Eloy Degen Signed-off-by: Magnus Karlsson Signed-off-by: Alexei Starovoitov Acked-by: Jonathan Lemon Link: https://lore.kernel.org/bpf/1571995035-21889-1-git-send-email-magnus.karlsson@intel.com Signed-off-by: Greg Kroah-Hartman

net-af_xdp: Use correct number of channels from ethtool

2019-12-31T15:45:40Z

[ Upstream commit 3de88c9113f88c04abda339f1aa629397bf89e02 ] Drivers use different fields to report the number of channels, so take the maximum of all data channels (rx, tx, combined) when determining the size of the xsk map. The current code used only 'combined' which was set to 0 in some drivers e.g. mlx4. Tested: compiled and run xdpsock -q 3 -r -S on mlx4 Signed-off-by: Luigi Rizzo Signed-off-by: Alexei Starovoitov Reviewed-by: Jakub Kicinski Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20191119001951.92930-1-lrizzo@google.com Signed-off-by: Sasha Levin

libbpf: Fix negative FD close() in xsk_setup_xdp_prog()

2019-12-31T15:45:05Z

[ Upstream commit 9656b346b280c3e49c8a116c3a715f966633b161 ] Fix issue reported by static analysis (Coverity). If bpf_prog_get_fd_by_id() fails, xsk_lookup_bpf_maps() will fail as well and clean-up code will attempt close() with fd=-1. Fix by checking bpf_prog_get_fd_by_id() return result and exiting early. Fixes: 10a13bb40e54 ("libbpf: remove qidconf and better support external bpf programs.") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20191107054059.313884-1-andriin@fb.com Signed-off-by: Sasha Levin

libbpf: Fix passing uninitialized bytes to setsockopt

2019-12-31T15:43:52Z

[ Upstream commit 25bfef430e960e695403b5d9c8dcc11b9f5d62be ] 'struct xdp_umem_reg' has 4 bytes of padding at the end that makes valgrind complain about passing uninitialized stack memory to the syscall: Syscall param socketcall.setsockopt() points to uninitialised byte(s) at 0x4E7AB7E: setsockopt (in /usr/lib64/libc-2.29.so) by 0x4BDE035: xsk_umem__create@@LIBBPF_0.0.4 (xsk.c:172) Uninitialised value was created by a stack allocation at 0x4BDDEBA: xsk_umem__create@@LIBBPF_0.0.4 (xsk.c:140) Padding bytes appeared after introducing of a new 'flags' field. memset() is required to clear them. Fixes: 10d30e301732 ("libbpf: add flags to umem config") Signed-off-by: Ilya Maximets Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20191009164929.17242-1-i.maximets@ovn.org Signed-off-by: Sasha Levin

libbpf: handle symbol versioning properly for libbpf.a

2019-09-30T22:19:45Z

bcc uses libbpf repo as a submodule. It brings in libbpf source code and builds everything together to produce shared libraries. With latest libbpf, I got the following errors: /bin/ld: libbcc_bpf.so.0.10.0: version node not found for symbol xsk_umem__create@LIBBPF_0.0.2 /bin/ld: failed to set dynamic section sizes: Bad value collect2: error: ld returned 1 exit status make[2]: *** [src/cc/libbcc_bpf.so.0.10.0] Error 1 In xsk.c, we have asm(".symver xsk_umem__create_v0_0_2, xsk_umem__create@LIBBPF_0.0.2"); asm(".symver xsk_umem__create_v0_0_4, xsk_umem__create@@LIBBPF_0.0.4"); The linker thinks the built is for LIBBPF but cannot find proper version LIBBPF_0.0.2/4, so emit errors. I also confirmed that using libbpf.a to produce a shared library also has issues: -bash-4.4$ cat t.c extern void *xsk_umem__create; void * test() { return xsk_umem__create; } -bash-4.4$ gcc -c -fPIC t.c -bash-4.4$ gcc -shared t.o libbpf.a -o t.so /bin/ld: t.so: version node not found for symbol xsk_umem__create@LIBBPF_0.0.2 /bin/ld: failed to set dynamic section sizes: Bad value collect2: error: ld returned 1 exit status -bash-4.4$ Symbol versioning does happens in commonly used libraries, e.g., elfutils and glibc. For static libraries, for a versioned symbol, the old definitions will be ignored, and the symbol will be an alias to the latest definition. For example, glibc sched_setaffinity is versioned. -bash-4.4$ readelf -s /usr/lib64/libc.so.6 | grep sched_setaffinity 756: 000000000013d3d0 13 FUNC GLOBAL DEFAULT 13 sched_setaffinity@GLIBC_2.3.3 757: 00000000000e2e70 455 FUNC GLOBAL DEFAULT 13 sched_setaffinity@@GLIBC_2.3.4 1800: 0000000000000000 0 FILE LOCAL DEFAULT ABS sched_setaffinity.c 4228: 00000000000e2e70 455 FUNC LOCAL DEFAULT 13 __sched_setaffinity_new 4648: 000000000013d3d0 13 FUNC LOCAL DEFAULT 13 __sched_setaffinity_old 7338: 000000000013d3d0 13 FUNC GLOBAL DEFAULT 13 sched_setaffinity@GLIBC_2 7380: 00000000000e2e70 455 FUNC GLOBAL DEFAULT 13 sched_setaffinity@@GLIBC_ -bash-4.4$ For static library, the definition of sched_setaffinity aliases to the new definition. -bash-4.4$ readelf -s /usr/lib64/libc.a | grep sched_setaffinity File: /usr/lib64/libc.a(sched_setaffinity.o) 8: 0000000000000000 455 FUNC GLOBAL DEFAULT 1 __sched_setaffinity_new 12: 0000000000000000 455 FUNC WEAK DEFAULT 1 sched_setaffinity For both elfutils and glibc, additional macros are used to control different handling of symbol versioning w.r.t static and shared libraries. For elfutils, the macro is SYMBOL_VERSIONING (https://sourceware.org/git/?p=elfutils.git;a=blob;f=lib/eu-config.h). For glibc, the macro is SHARED (https://sourceware.org/git/?p=glibc.git;a=blob;f=include/shlib-compat.h;hb=refs/heads/master) This patch used SHARED as the macro name. After this patch, the libbpf.a has -bash-4.4$ readelf -s libbpf.a | grep xsk_umem__create 372: 0000000000017145 1190 FUNC GLOBAL DEFAULT 1 xsk_umem__create_v0_0_4 405: 0000000000017145 1190 FUNC GLOBAL DEFAULT 1 xsk_umem__create 499: 00000000000175eb 103 FUNC GLOBAL DEFAULT 1 xsk_umem__create_v0_0_2 -bash-4.4$ No versioned symbols for xsk_umem__create. The libbpf.a can be used to build a shared library succesfully. -bash-4.4$ cat t.c extern void *xsk_umem__create; void * test() { return xsk_umem__create; } -bash-4.4$ gcc -c -fPIC t.c -bash-4.4$ gcc -shared t.o libbpf.a -o t.so -bash-4.4$ Fixes: 10d30e301732 ("libbpf: add flags to umem config") Cc: Kevin Laatz Cc: Arnaldo Carvalho de Melo Cc: Andrii Nakryiko Acked-by: Andrii Nakryiko Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov

libbpf: Remove getsockopt() check for XDP_OPTIONS

2019-09-19T12:22:18Z

The xsk_socket__create() function fails and returns an error if it cannot get the XDP_OPTIONS through getsockopt(). However, support for XDP_OPTIONS was not added until kernel 5.3, so this means that creating XSK sockets always fails on older kernels. Since the option is just used to set the zero-copy flag in the xsk struct, and that flag is not really used for anything yet, just remove the getsockopt() call until a proper use for it is introduced. Suggested-by: Yonghong Song Signed-off-by: Toke Høiland-Jørgensen Acked-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann

libbpf: add flags to umem config

2019-08-30T23:08:26Z

This patch adds a 'flags' field to the umem_config and umem_reg structs. This will allow for more options to be added for configuring umems. The first use for the flags field is to add a flag for unaligned chunks mode. These flags can either be user-provided or filled with a default. Since we change the size of the xsk_umem_config struct, we need to version the ABI. This patch includes the ABI versioning for xsk_umem__create. The Makefile was also updated to handle multiple function versions in check-abi. Signed-off-by: Kevin Laatz Signed-off-by: Ciara Loftus Acked-by: Jonathan Lemon Signed-off-by: Daniel Borkmann

libbpf: use LFS (_FILE_OFFSET_BITS) instead of direct mmap2 syscall

2019-08-21T12:31:17Z

Drop __NR_mmap2 fork in flavor of LFS, that is _FILE_OFFSET_BITS=64 (glibc & bionic) / LARGEFILE64_SOURCE (for musl) decision. It allows mmap() to use 64bit offset that is passed to mmap2 syscall. As result pgoff is not truncated and no need to use direct access to mmap2 for 32 bits systems. Signed-off-by: Ivan Khoronzhuk Acked-by: Yonghong Song Signed-off-by: Daniel Borkmann

libbpf: add support for need_wakeup flag in AF_XDP part

2019-08-17T21:07:32Z

This commit adds support for the new need_wakeup flag in AF_XDP. The xsk_socket__create function is updated to handle this and a new function is introduced called xsk_ring_prod__needs_wakeup(). This function can be used by the application to check if Rx and/or Tx processing needs to be explicitly woken up. Signed-off-by: Magnus Karlsson Acked-by: Jonathan Lemon Signed-off-by: Daniel Borkmann