From a0e0018c9a7ef5ce7f6d2c3ae16aecbbd16a8f67 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 16:18:53 +0200 Subject: Adding upstream version 6.1.0. Signed-off-by: Daniel Baumann --- examples/bpf/legacy/bpf_graft.c | 66 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 examples/bpf/legacy/bpf_graft.c (limited to 'examples/bpf/legacy/bpf_graft.c') diff --git a/examples/bpf/legacy/bpf_graft.c b/examples/bpf/legacy/bpf_graft.c new file mode 100644 index 0000000..f4c920c --- /dev/null +++ b/examples/bpf/legacy/bpf_graft.c @@ -0,0 +1,66 @@ +#include "../../../include/bpf_api.h" + +/* This example demonstrates how classifier run-time behaviour + * can be altered with tail calls. We start out with an empty + * jmp_tc array, then add section aaa to the array slot 0, and + * later on atomically replace it with section bbb. Note that + * as shown in other examples, the tc loader can prepopulate + * tail called sections, here we start out with an empty one + * on purpose to show it can also be done this way. + * + * tc filter add dev foo parent ffff: bpf obj graft.o + * tc exec bpf dbg + * [...] + * Socket Thread-20229 [001] ..s. 138993.003923: : fallthrough + * -0 [001] ..s. 138993.202265: : fallthrough + * Socket Thread-20229 [001] ..s. 138994.004149: : fallthrough + * [...] + * + * tc exec bpf graft m:globals/jmp_tc key 0 obj graft.o sec aaa + * tc exec bpf dbg + * [...] + * Socket Thread-19818 [002] ..s. 139012.053587: : aaa + * -0 [002] ..s. 139012.172359: : aaa + * Socket Thread-19818 [001] ..s. 139012.173556: : aaa + * [...] + * + * tc exec bpf graft m:globals/jmp_tc key 0 obj graft.o sec bbb + * tc exec bpf dbg + * [...] + * Socket Thread-19818 [002] ..s. 139022.102967: : bbb + * -0 [002] ..s. 139022.155640: : bbb + * Socket Thread-19818 [001] ..s. 139022.156730: : bbb + * [...] + */ + +struct bpf_elf_map __section_maps jmp_tc = { + .type = BPF_MAP_TYPE_PROG_ARRAY, + .size_key = sizeof(uint32_t), + .size_value = sizeof(uint32_t), + .pinning = PIN_GLOBAL_NS, + .max_elem = 1, +}; + +__section("aaa") +int cls_aaa(struct __sk_buff *skb) +{ + printt("aaa\n"); + return TC_H_MAKE(1, 42); +} + +__section("bbb") +int cls_bbb(struct __sk_buff *skb) +{ + printt("bbb\n"); + return TC_H_MAKE(1, 43); +} + +__section_cls_entry +int cls_entry(struct __sk_buff *skb) +{ + tail_call(skb, &jmp_tc, 0); + printt("fallthrough\n"); + return BPF_H_DEFAULT; +} + +BPF_LICENSE("GPL"); -- cgit v1.2.3