diff options
Diffstat (limited to 'tools/testing/selftests/bpf/progs/kfree_skb.c')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/kfree_skb.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/kfree_skb.c b/tools/testing/selftests/bpf/progs/kfree_skb.c new file mode 100644 index 000000000000..974d6f3bb319 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/kfree_skb.c @@ -0,0 +1,153 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2019 Facebook +#include <linux/bpf.h> +#include <stdbool.h> +#include "bpf_helpers.h" +#include "bpf_endian.h" +#include "bpf_trace_helpers.h" + +char _license[] SEC("license") = "GPL"; +struct { + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); + __uint(key_size, sizeof(int)); + __uint(value_size, sizeof(int)); +} perf_buf_map SEC(".maps"); + +#define _(P) (__builtin_preserve_access_index(P)) + +/* define few struct-s that bpf program needs to access */ +struct callback_head { + struct callback_head *next; + void (*func)(struct callback_head *head); +}; +struct dev_ifalias { + struct callback_head rcuhead; +}; + +struct net_device /* same as kernel's struct net_device */ { + int ifindex; + struct dev_ifalias *ifalias; +}; + +typedef struct { + int counter; +} atomic_t; +typedef struct refcount_struct { + atomic_t refs; +} refcount_t; + +struct sk_buff { + /* field names and sizes should match to those in the kernel */ + unsigned int len, data_len; + __u16 mac_len, hdr_len, queue_mapping; + struct net_device *dev; + /* order of the fields doesn't matter */ + refcount_t users; + unsigned char *data; + char __pkt_type_offset[0]; + char cb[48]; +}; + +struct meta { + int ifindex; + __u32 cb32_0; + __u8 cb8_0; +}; + +/* TRACE_EVENT(kfree_skb, + * TP_PROTO(struct sk_buff *skb, void *location), + */ +BPF_TRACE_2("tp_btf/kfree_skb", trace_kfree_skb, + struct sk_buff *, skb, void *, location) +{ + struct net_device *dev; + struct callback_head *ptr; + void *func; + int users; + unsigned char *data; + unsigned short pkt_data; + struct meta meta = {}; + char pkt_type; + __u32 *cb32; + __u8 *cb8; + + __builtin_preserve_access_index(({ + users = skb->users.refs.counter; + data = skb->data; + dev = skb->dev; + ptr = dev->ifalias->rcuhead.next; + func = ptr->func; + cb8 = (__u8 *)&skb->cb; + cb32 = (__u32 *)&skb->cb; + })); + + meta.ifindex = _(dev->ifindex); + meta.cb8_0 = cb8[8]; + meta.cb32_0 = cb32[2]; + + bpf_probe_read_kernel(&pkt_type, sizeof(pkt_type), _(&skb->__pkt_type_offset)); + pkt_type &= 7; + + /* read eth proto */ + bpf_probe_read_kernel(&pkt_data, sizeof(pkt_data), data + 12); + + bpf_printk("rcuhead.next %llx func %llx\n", ptr, func); + bpf_printk("skb->len %d users %d pkt_type %x\n", + _(skb->len), users, pkt_type); + bpf_printk("skb->queue_mapping %d\n", _(skb->queue_mapping)); + bpf_printk("dev->ifindex %d data %llx pkt_data %x\n", + meta.ifindex, data, pkt_data); + bpf_printk("cb8_0:%x cb32_0:%x\n", meta.cb8_0, meta.cb32_0); + + if (users != 1 || pkt_data != bpf_htons(0x86dd) || meta.ifindex != 1) + /* raw tp ignores return value */ + return 0; + + /* send first 72 byte of the packet to user space */ + bpf_skb_output(skb, &perf_buf_map, (72ull << 32) | BPF_F_CURRENT_CPU, + &meta, sizeof(meta)); + return 0; +} + +static volatile struct { + bool fentry_test_ok; + bool fexit_test_ok; +} result; + +BPF_TRACE_3("fentry/eth_type_trans", fentry_eth_type_trans, + struct sk_buff *, skb, struct net_device *, dev, + unsigned short, protocol) +{ + int len, ifindex; + + __builtin_preserve_access_index(({ + len = skb->len; + ifindex = dev->ifindex; + })); + + /* fentry sees full packet including L2 header */ + if (len != 74 || ifindex != 1) + return 0; + result.fentry_test_ok = true; + return 0; +} + +BPF_TRACE_3("fexit/eth_type_trans", fexit_eth_type_trans, + struct sk_buff *, skb, struct net_device *, dev, + unsigned short, protocol) +{ + int len, ifindex; + + __builtin_preserve_access_index(({ + len = skb->len; + ifindex = dev->ifindex; + })); + + /* fexit sees packet without L2 header that eth_type_trans should have + * consumed. + */ + if (len != 60 || protocol != bpf_htons(0x86dd) || ifindex != 1) + return 0; + result.fexit_test_ok = true; + return 0; +} |