From dda2caafadf081761acf87145dce5a49ea68c1ca Mon Sep 17 00:00:00 2001 From: Roman Arutyunyan Date: Tue, 24 Sep 2024 14:53:45 +0400 Subject: [PATCH] QUIC: fixed bpf compilation with newer Linux kernels. QUIC bpf program previously used struct bpf_map_def which was deprecated in [1] (kernel version 5.18) and removed in [2] (kernel 6.1). New-style BTF map definitions were added in [3] (linux kernel 5.3). Switching the program no BTF is however not necessary since nginx has its own relocation procedure which allows referencing the real map structure by its file descriptor allocated earlier. In particular, bpf instruction BPF_LD_IMM64 (0x18/0x0) is substituted with instruction BPF_LD_MAP_FD (0x18/0x1) and map_fd is stored in the imm field, see [4] and [5] for details. To fix compilation, struct bpf_map_def is changed to a known type (int) and "extern" is added to indicate external linkage and reduce object file size. [1] https://github.com/torvalds/linux/commit/93b8952d223af03c51fba0c6258173d2ffbd2cb7 [2] https://github.com/torvalds/linux/commit/dc567045f1590f6460d3e9a6ea6ad5e600b58b84 [3] https://github.com/torvalds/linux/commit/abd29c9314595b1ee5ec6c61d7c49a497ffb30a3 [4] https://github.com/torvalds/linux/blob/master/include/linux/filter.h [5] https://datatracker.ietf.org/doc/draft-ietf-bpf-isa/04/ --- .../quic/bpf/ngx_quic_reuseport_helper.c | 2 +- src/event/quic/ngx_event_quic_bpf_code.c | 47 ++++++++++--------- 2 files changed, 27 insertions(+), 22 deletions(-) diff --git a/src/event/quic/bpf/ngx_quic_reuseport_helper.c b/src/event/quic/bpf/ngx_quic_reuseport_helper.c index 999e7607c..51b78f043 100644 --- a/src/event/quic/bpf/ngx_quic_reuseport_helper.c +++ b/src/event/quic/bpf/ngx_quic_reuseport_helper.c @@ -67,7 +67,7 @@ char _license[] SEC("license") = LICENSE; * actual map object is created by the "bpf" system call, * all pointers to this variable are replaced by the bpf loader */ -struct bpf_map_def SEC("maps") ngx_quic_sockmap; +extern int ngx_quic_sockmap; SEC(PROGNAME) diff --git a/src/event/quic/ngx_event_quic_bpf_code.c b/src/event/quic/ngx_event_quic_bpf_code.c index 5c9dea1c1..625f40405 100644 --- a/src/event/quic/ngx_event_quic_bpf_code.c +++ b/src/event/quic/ngx_event_quic_bpf_code.c @@ -7,38 +7,42 @@ static ngx_bpf_reloc_t bpf_reloc_prog_ngx_quic_reuseport_helper[] = { - { "ngx_quic_sockmap", 55 }, + { "ngx_quic_sockmap", 59 }, }; static struct bpf_insn bpf_insn_prog_ngx_quic_reuseport_helper[] = { /* opcode dst src offset imm */ - { 0x79, BPF_REG_4, BPF_REG_1, (int16_t) 0, 0x0 }, + { 0x79, BPF_REG_2, BPF_REG_1, (int16_t) 0, 0x0 }, { 0x79, BPF_REG_3, BPF_REG_1, (int16_t) 8, 0x0 }, - { 0xbf, BPF_REG_2, BPF_REG_4, (int16_t) 0, 0x0 }, - { 0x7, BPF_REG_2, BPF_REG_0, (int16_t) 0, 0x8 }, - { 0x2d, BPF_REG_2, BPF_REG_3, (int16_t) 54, 0x0 }, - { 0xbf, BPF_REG_5, BPF_REG_4, (int16_t) 0, 0x0 }, - { 0x7, BPF_REG_5, BPF_REG_0, (int16_t) 0, 0x9 }, - { 0x2d, BPF_REG_5, BPF_REG_3, (int16_t) 51, 0x0 }, + { 0xbf, BPF_REG_6, BPF_REG_2, (int16_t) 0, 0x0 }, + { 0x7, BPF_REG_6, BPF_REG_0, (int16_t) 0, 0x8 }, + { 0x2d, BPF_REG_6, BPF_REG_3, (int16_t) 58, 0x0 }, + { 0xbf, BPF_REG_4, BPF_REG_2, (int16_t) 0, 0x0 }, + { 0x7, BPF_REG_4, BPF_REG_0, (int16_t) 0, 0x9 }, + { 0x2d, BPF_REG_4, BPF_REG_3, (int16_t) 55, 0x0 }, + { 0xb7, BPF_REG_4, BPF_REG_0, (int16_t) 0, 0x8 }, { 0xb7, BPF_REG_5, BPF_REG_0, (int16_t) 0, 0x14 }, { 0xb7, BPF_REG_0, BPF_REG_0, (int16_t) 0, 0x9 }, - { 0x71, BPF_REG_6, BPF_REG_2, (int16_t) 0, 0x0 }, + { 0x71, BPF_REG_6, BPF_REG_6, (int16_t) 0, 0x0 }, { 0x67, BPF_REG_6, BPF_REG_0, (int16_t) 0, 0x38 }, { 0xc7, BPF_REG_6, BPF_REG_0, (int16_t) 0, 0x38 }, - { 0x65, BPF_REG_6, BPF_REG_0, (int16_t) 10, 0xffffffff }, - { 0xbf, BPF_REG_2, BPF_REG_4, (int16_t) 0, 0x0 }, - { 0x7, BPF_REG_2, BPF_REG_0, (int16_t) 0, 0xd }, - { 0x2d, BPF_REG_2, BPF_REG_3, (int16_t) 42, 0x0 }, - { 0xbf, BPF_REG_5, BPF_REG_4, (int16_t) 0, 0x0 }, - { 0x7, BPF_REG_5, BPF_REG_0, (int16_t) 0, 0xe }, - { 0x2d, BPF_REG_5, BPF_REG_3, (int16_t) 39, 0x0 }, + { 0x65, BPF_REG_6, BPF_REG_0, (int16_t) 11, 0xffffffff }, + { 0xbf, BPF_REG_5, BPF_REG_2, (int16_t) 0, 0x0 }, + { 0x7, BPF_REG_5, BPF_REG_0, (int16_t) 0, 0xd }, + { 0x2d, BPF_REG_5, BPF_REG_3, (int16_t) 45, 0x0 }, + { 0xbf, BPF_REG_4, BPF_REG_2, (int16_t) 0, 0x0 }, + { 0x7, BPF_REG_4, BPF_REG_0, (int16_t) 0, 0xe }, + { 0x2d, BPF_REG_4, BPF_REG_3, (int16_t) 42, 0x0 }, + { 0xb7, BPF_REG_4, BPF_REG_0, (int16_t) 0, 0xd }, { 0xb7, BPF_REG_0, BPF_REG_0, (int16_t) 0, 0xe }, - { 0x71, BPF_REG_5, BPF_REG_2, (int16_t) 0, 0x0 }, + { 0x71, BPF_REG_5, BPF_REG_5, (int16_t) 0, 0x0 }, { 0xb7, BPF_REG_6, BPF_REG_0, (int16_t) 0, 0x8 }, - { 0x2d, BPF_REG_6, BPF_REG_5, (int16_t) 35, 0x0 }, - { 0xf, BPF_REG_5, BPF_REG_0, (int16_t) 0, 0x0 }, - { 0xf, BPF_REG_4, BPF_REG_5, (int16_t) 0, 0x0 }, - { 0x2d, BPF_REG_4, BPF_REG_3, (int16_t) 32, 0x0 }, + { 0x2d, BPF_REG_6, BPF_REG_5, (int16_t) 37, 0x0 }, + { 0xbf, BPF_REG_6, BPF_REG_2, (int16_t) 0, 0x0 }, + { 0xf, BPF_REG_6, BPF_REG_0, (int16_t) 0, 0x0 }, + { 0xf, BPF_REG_6, BPF_REG_5, (int16_t) 0, 0x0 }, + { 0x2d, BPF_REG_6, BPF_REG_3, (int16_t) 33, 0x0 }, + { 0xf, BPF_REG_2, BPF_REG_4, (int16_t) 0, 0x0 }, { 0xbf, BPF_REG_4, BPF_REG_2, (int16_t) 0, 0x0 }, { 0x7, BPF_REG_4, BPF_REG_0, (int16_t) 0, 0x9 }, { 0x2d, BPF_REG_4, BPF_REG_3, (int16_t) 29, 0x0 }, @@ -86,3 +90,4 @@ ngx_bpf_program_t ngx_quic_reuseport_helper = { .license = "BSD", .type = BPF_PROG_TYPE_SK_REUSEPORT, }; +