diff options
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/bpf/Makefile | 4 | ||||
| -rw-r--r-- | samples/bpf/sock_example.c | 4 | ||||
| -rw-r--r-- | samples/bpf/xdp_adjust_tail_kern.c | 152 | ||||
| -rw-r--r-- | samples/bpf/xdp_adjust_tail_user.c | 142 | ||||
| -rw-r--r-- | samples/bpf/xdp_monitor_user.c | 2 |
5 files changed, 301 insertions, 3 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 4d6a6edd4bf6..aa8c392e2e52 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -44,6 +44,7 @@ hostprogs-y += xdp_monitor hostprogs-y += xdp_rxq_info hostprogs-y += syscall_tp hostprogs-y += cpustat +hostprogs-y += xdp_adjust_tail # Libbpf dependencies LIBBPF := ../../tools/lib/bpf/bpf.o ../../tools/lib/bpf/nlattr.o @@ -95,6 +96,7 @@ xdp_monitor-objs := bpf_load.o $(LIBBPF) xdp_monitor_user.o xdp_rxq_info-objs := bpf_load.o $(LIBBPF) xdp_rxq_info_user.o syscall_tp-objs := bpf_load.o $(LIBBPF) syscall_tp_user.o cpustat-objs := bpf_load.o $(LIBBPF) cpustat_user.o +xdp_adjust_tail-objs := bpf_load.o $(LIBBPF) xdp_adjust_tail_user.o # Tell kbuild to always build the programs always := $(hostprogs-y) @@ -148,6 +150,7 @@ always += xdp_rxq_info_kern.o always += xdp2skb_meta_kern.o always += syscall_tp_kern.o always += cpustat_kern.o +always += xdp_adjust_tail_kern.o HOSTCFLAGS += -I$(objtree)/usr/include HOSTCFLAGS += -I$(srctree)/tools/lib/ @@ -193,6 +196,7 @@ HOSTLOADLIBES_xdp_monitor += -lelf HOSTLOADLIBES_xdp_rxq_info += -lelf HOSTLOADLIBES_syscall_tp += -lelf HOSTLOADLIBES_cpustat += -lelf +HOSTLOADLIBES_xdp_adjust_tail += -lelf # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline: # make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang diff --git a/samples/bpf/sock_example.c b/samples/bpf/sock_example.c index 6fc6e193ef1b..33a637507c00 100644 --- a/samples/bpf/sock_example.c +++ b/samples/bpf/sock_example.c @@ -9,10 +9,10 @@ * if (value) * (*(u64*)value) += 1; * - * - attaches this program to eth0 raw socket + * - attaches this program to loopback interface "lo" raw socket * * - every second user space reads map[tcp], map[udp], map[icmp] to see - * how many packets of given protocol were seen on eth0 + * how many packets of given protocol were seen on "lo" */ #include <stdio.h> #include <unistd.h> diff --git a/samples/bpf/xdp_adjust_tail_kern.c b/samples/bpf/xdp_adjust_tail_kern.c new file mode 100644 index 000000000000..411fdb21f8bc --- /dev/null +++ b/samples/bpf/xdp_adjust_tail_kern.c @@ -0,0 +1,152 @@ +/* SPDX-License-Identifier: GPL-2.0 + * Copyright (c) 2018 Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * This program shows how to use bpf_xdp_adjust_tail() by + * generating ICMPv4 "packet to big" (unreachable/ df bit set frag needed + * to be more preice in case of v4)" where receiving packets bigger then + * 600 bytes. + */ +#define KBUILD_MODNAME "foo" +#include <uapi/linux/bpf.h> +#include <linux/in.h> +#include <linux/if_ether.h> +#include <linux/if_packet.h> +#include <linux/if_vlan.h> +#include <linux/ip.h> +#include <linux/icmp.h> +#include "bpf_helpers.h" + +#define DEFAULT_TTL 64 +#define MAX_PCKT_SIZE 600 +#define ICMP_TOOBIG_SIZE 98 +#define ICMP_TOOBIG_PAYLOAD_SIZE 92 + +struct bpf_map_def SEC("maps") icmpcnt = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(__u32), + .value_size = sizeof(__u64), + .max_entries = 1, +}; + +static __always_inline void count_icmp(void) +{ + u64 key = 0; + u64 *icmp_count; + + icmp_count = bpf_map_lookup_elem(&icmpcnt, &key); + if (icmp_count) + *icmp_count += 1; +} + +static __always_inline void swap_mac(void *data, struct ethhdr *orig_eth) +{ + struct ethhdr *eth; + + eth = data; + memcpy(eth->h_source, orig_eth->h_dest, ETH_ALEN); + memcpy(eth->h_dest, orig_eth->h_source, ETH_ALEN); + eth->h_proto = orig_eth->h_proto; +} + +static __always_inline __u16 csum_fold_helper(__u32 csum) +{ + return ~((csum & 0xffff) + (csum >> 16)); +} + +static __always_inline void ipv4_csum(void *data_start, int data_size, + __u32 *csum) +{ + *csum = bpf_csum_diff(0, 0, data_start, data_size, *csum); + *csum = csum_fold_helper(*csum); +} + +static __always_inline int send_icmp4_too_big(struct xdp_md *xdp) +{ + int headroom = (int)sizeof(struct iphdr) + (int)sizeof(struct icmphdr); + + if (bpf_xdp_adjust_head(xdp, 0 - headroom)) + return XDP_DROP; + void *data = (void *)(long)xdp->data; + void *data_end = (void *)(long)xdp->data_end; + + if (data + (ICMP_TOOBIG_SIZE + headroom) > data_end) + return XDP_DROP; + + struct iphdr *iph, *orig_iph; + struct icmphdr *icmp_hdr; + struct ethhdr *orig_eth; + __u32 csum = 0; + __u64 off = 0; + + orig_eth = data + headroom; + swap_mac(data, orig_eth); + off += sizeof(struct ethhdr); + iph = data + off; + off += sizeof(struct iphdr); + icmp_hdr = data + off; + off += sizeof(struct icmphdr); + orig_iph = data + off; + icmp_hdr->type = ICMP_DEST_UNREACH; + icmp_hdr->code = ICMP_FRAG_NEEDED; + icmp_hdr->un.frag.mtu = htons(MAX_PCKT_SIZE-sizeof(struct ethhdr)); + icmp_hdr->checksum = 0; + ipv4_csum(icmp_hdr, ICMP_TOOBIG_PAYLOAD_SIZE, &csum); + icmp_hdr->checksum = csum; + iph->ttl = DEFAULT_TTL; + iph->daddr = orig_iph->saddr; + iph->saddr = orig_iph->daddr; + iph->version = 4; + iph->ihl = 5; + iph->protocol = IPPROTO_ICMP; + iph->tos = 0; + iph->tot_len = htons( + ICMP_TOOBIG_SIZE + headroom - sizeof(struct ethhdr)); + iph->check = 0; + csum = 0; + ipv4_csum(iph, sizeof(struct iphdr), &csum); + iph->check = csum; + count_icmp(); + return XDP_TX; +} + + +static __always_inline int handle_ipv4(struct xdp_md *xdp) +{ + void *data_end = (void *)(long)xdp->data_end; + void *data = (void *)(long)xdp->data; + int pckt_size = data_end - data; + int offset; + + if (pckt_size > MAX_PCKT_SIZE) { + offset = pckt_size - ICMP_TOOBIG_SIZE; + if (bpf_xdp_adjust_tail(xdp, 0 - offset)) + return XDP_PASS; + return send_icmp4_too_big(xdp); + } + return XDP_PASS; +} + +SEC("xdp_icmp") +int _xdp_icmp(struct xdp_md *xdp) +{ + void *data_end = (void *)(long)xdp->data_end; + void *data = (void *)(long)xdp->data; + struct ethhdr *eth = data; + __u16 h_proto; + + if (eth + 1 > data_end) + return XDP_DROP; + + h_proto = eth->h_proto; + + if (h_proto == htons(ETH_P_IP)) + return handle_ipv4(xdp); + else + return XDP_PASS; +} + +char _license[] SEC("license") = "GPL"; diff --git a/samples/bpf/xdp_adjust_tail_user.c b/samples/bpf/xdp_adjust_tail_user.c new file mode 100644 index 000000000000..f621a541b574 --- /dev/null +++ b/samples/bpf/xdp_adjust_tail_user.c @@ -0,0 +1,142 @@ +/* SPDX-License-Identifier: GPL-2.0 + * Copyright (c) 2018 Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include <linux/bpf.h> +#include <linux/if_link.h> +#include <assert.h> +#include <errno.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/resource.h> +#include <arpa/inet.h> +#include <netinet/ether.h> +#include <unistd.h> +#include <time.h> +#include "bpf_load.h" +#include "libbpf.h" +#include "bpf_util.h" + +#define STATS_INTERVAL_S 2U + +static int ifindex = -1; +static __u32 xdp_flags; + +static void int_exit(int sig) +{ + if (ifindex > -1) + bpf_set_link_xdp_fd(ifindex, -1, xdp_flags); + exit(0); +} + +/* simple "icmp packet too big sent" counter + */ +static void poll_stats(unsigned int kill_after_s) +{ + time_t started_at = time(NULL); + __u64 value = 0; + int key = 0; + + + while (!kill_after_s || time(NULL) - started_at <= kill_after_s) { + sleep(STATS_INTERVAL_S); + + assert(bpf_map_lookup_elem(map_fd[0], &key, &value) == 0); + + printf("icmp \"packet too big\" sent: %10llu pkts\n", value); + } +} + +static void usage(const char *cmd) +{ + printf("Start a XDP prog which send ICMP \"packet too big\" \n" + "messages if ingress packet is bigger then MAX_SIZE bytes\n"); + printf("Usage: %s [...]\n", cmd); + printf(" -i <ifindex> Interface Index\n"); + printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n"); + printf(" -S use skb-mode\n"); + printf(" -N enforce native mode\n"); + printf(" -h Display this help\n"); +} + +int main(int argc, char **argv) +{ + unsigned char opt_flags[256] = {}; + unsigned int kill_after_s = 0; + const char *optstr = "i:T:SNh"; + struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; + char filename[256]; + int opt; + int i; + + + for (i = 0; i < strlen(optstr); i++) + if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z') + opt_flags[(unsigned char)optstr[i]] = 1; + + while ((opt = getopt(argc, argv, optstr)) != -1) { + + switch (opt) { + case 'i': + ifindex = atoi(optarg); + break; + case 'T': + kill_after_s = atoi(optarg); + break; + case 'S': + xdp_flags |= XDP_FLAGS_SKB_MODE; + break; + case 'N': + xdp_flags |= XDP_FLAGS_DRV_MODE; + break; + default: + usage(argv[0]); + return 1; + } + opt_flags[opt] = 0; + } + + for (i = 0; i < strlen(optstr); i++) { + if (opt_flags[(unsigned int)optstr[i]]) { + fprintf(stderr, "Missing argument -%c\n", optstr[i]); + usage(argv[0]); + return 1; + } + } + + if (setrlimit(RLIMIT_MEMLOCK, &r)) { + perror("setrlimit(RLIMIT_MEMLOCK, RLIM_INFINITY)"); + return 1; + } + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + if (!prog_fd[0]) { + printf("load_bpf_file: %s\n", strerror(errno)); + return 1; + } + + signal(SIGINT, int_exit); + signal(SIGTERM, int_exit); + + if (bpf_set_link_xdp_fd(ifindex, prog_fd[0], xdp_flags) < 0) { + printf("link set xdp fd failed\n"); + return 1; + } + + poll_stats(kill_after_s); + + bpf_set_link_xdp_fd(ifindex, -1, xdp_flags); + + return 0; +} diff --git a/samples/bpf/xdp_monitor_user.c b/samples/bpf/xdp_monitor_user.c index eec14520d513..894bc64c2cac 100644 --- a/samples/bpf/xdp_monitor_user.c +++ b/samples/bpf/xdp_monitor_user.c @@ -330,7 +330,7 @@ static void stats_print(struct stats_record *stats_rec, pps = calc_pps_u64(r, p, t); if (pps > 0) printf(fmt1, "Exception", i, - 0.0, pps, err2str(rec_i)); + 0.0, pps, action2str(rec_i)); } pps = calc_pps_u64(&rec->total, &prev->total, t); if (pps > 0) |