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QUIC: fixed bpf compilation with newer Linux kernels.

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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] 93b8952d22
[2] dc567045f1
[3] abd29c9314
[4] https://github.com/torvalds/linux/blob/master/include/linux/filter.h
[5] https://datatracker.ietf.org/doc/draft-ietf-bpf-isa/04/
This commit is contained in:
Roman Arutyunyan 2024-09-24 14:53:45 +04:00
parent 51857ce404
commit dda2caafad
2 changed files with 27 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/event/quic/bpf/ngx_quic_reuseport_helper.c
View File

@ -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)

47
src/event/quic/ngx_event_quic_bpf_code.c
View File

@ -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,
};