diff options
| -rw-r--r-- | samples/bpf/Makefile | 1 | ||||
| -rw-r--r-- | samples/bpf/tcp_tos_reflect_kern.c | 87 |
2 files changed, 88 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 36f9f41d094b..be0a961450bc 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -153,6 +153,7 @@ always += tcp_cong_kern.o always += tcp_iw_kern.o always += tcp_clamp_kern.o always += tcp_basertt_kern.o +always += tcp_tos_reflect_kern.o always += xdp_redirect_kern.o always += xdp_redirect_map_kern.o always += xdp_redirect_cpu_kern.o diff --git a/samples/bpf/tcp_tos_reflect_kern.c b/samples/bpf/tcp_tos_reflect_kern.c new file mode 100644 index 000000000000..d51dab19eca6 --- /dev/null +++ b/samples/bpf/tcp_tos_reflect_kern.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2018 Facebook + * + * BPF program to automatically reflect TOS option from received syn packet + * + * Use load_sock_ops to load this BPF program. + */ + +#include <uapi/linux/bpf.h> +#include <uapi/linux/tcp.h> +#include <uapi/linux/if_ether.h> +#include <uapi/linux/if_packet.h> +#include <uapi/linux/ip.h> +#include <uapi/linux/ipv6.h> +#include <uapi/linux/in.h> +#include <linux/socket.h> +#include "bpf_helpers.h" +#include "bpf_endian.h" + +#define DEBUG 1 + +#define bpf_printk(fmt, ...) \ +({ \ + char ____fmt[] = fmt; \ + bpf_trace_printk(____fmt, sizeof(____fmt), \ + ##__VA_ARGS__); \ +}) + +SEC("sockops") +int bpf_basertt(struct bpf_sock_ops *skops) +{ + char header[sizeof(struct ipv6hdr)]; + struct ipv6hdr *hdr6; + struct iphdr *hdr; + int hdr_size = 0; + int save_syn = 1; + int tos = 0; + int rv = 0; + int op; + + op = (int) skops->op; + +#ifdef DEBUG + bpf_printk("BPF command: %d\n", op); +#endif + switch (op) { + case BPF_SOCK_OPS_TCP_LISTEN_CB: + rv = bpf_setsockopt(skops, SOL_TCP, TCP_SAVE_SYN, + &save_syn, sizeof(save_syn)); + break; + case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: + if (skops->family == AF_INET) + hdr_size = sizeof(struct iphdr); + else + hdr_size = sizeof(struct ipv6hdr); + rv = bpf_getsockopt(skops, SOL_TCP, TCP_SAVED_SYN, + header, hdr_size); + if (!rv) { + if (skops->family == AF_INET) { + hdr = (struct iphdr *) header; + tos = hdr->tos; + if (tos != 0) + bpf_setsockopt(skops, SOL_IP, IP_TOS, + &tos, sizeof(tos)); + } else { + hdr6 = (struct ipv6hdr *) header; + tos = ((hdr6->priority) << 4 | + (hdr6->flow_lbl[0]) >> 4); + if (tos) + bpf_setsockopt(skops, SOL_IPV6, + IPV6_TCLASS, + &tos, sizeof(tos)); + } + rv = 0; + } + break; + default: + rv = -1; + } +#ifdef DEBUG + bpf_printk("Returning %d\n", rv); +#endif + skops->reply = rv; + return 1; +} +char _license[] SEC("license") = "GPL"; |