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Add packet04-tailgrow
Start with trimmed down version of packet-solution files. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
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‎packet04-tailgrow/Makefile‎

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# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
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XDP_TARGETS := xdp_prog_kern
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USER_TARGETS := xdp_prog_user
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LIBBPF_DIR = ../libbpf/src/
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COMMON_DIR = ../common
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COPY_LOADER := xdp_loader
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COPY_STATS := xdp_stats
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EXTRA_DEPS := $(COMMON_DIR)/parsing_helpers.h
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include $(COMMON_DIR)/common.mk

‎packet04-tailgrow/xdp_prog_kern.c‎

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/* SPDX-License-Identifier: GPL-2.0 */
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#include <linux/bpf.h>
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#include <linux/in.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_endian.h>
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// The parsing helper functions from the packet01 lesson have moved here
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#include "../common/parsing_helpers.h"
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#include "../common/rewrite_helpers.h"
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/* Defines xdp_stats_map */
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#include "../common/xdp_stats_kern_user.h"
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#include "../common/xdp_stats_kern.h"
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#ifndef memcpy
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#define memcpy(dest, src, n) __builtin_memcpy((dest), (src), (n))
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#endif
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struct bpf_map_def SEC("maps") tx_port = {
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.type = BPF_MAP_TYPE_DEVMAP,
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.key_size = sizeof(int),
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.value_size = sizeof(int),
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.max_entries = 256,
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};
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struct bpf_map_def SEC("maps") redirect_params = {
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.type = BPF_MAP_TYPE_HASH,
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.key_size = ETH_ALEN,
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.value_size = ETH_ALEN,
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.max_entries = 1,
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};
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/* Solution to packet03/assignment-2 */
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SEC("xdp_redirect")
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int xdp_redirect_func(struct xdp_md *ctx)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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struct hdr_cursor nh;
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struct ethhdr *eth;
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int eth_type;
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int action = XDP_PASS;
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unsigned char dst[ETH_ALEN] = { /* TODO: put your values here */ };
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unsigned ifindex = 0/* TODO: put your values here */;
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/* These keep track of the next header type and iterator pointer */
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nh.pos = data;
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/* Parse Ethernet and IP/IPv6 headers */
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eth_type = parse_ethhdr(&nh, data_end, &eth);
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if (eth_type == -1)
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goto out;
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/* Set a proper destination address */
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memcpy(eth->h_dest, dst, ETH_ALEN);
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action = bpf_redirect(ifindex, 0);
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out:
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return xdp_stats_record_action(ctx, action);
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}
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/* Solution to packet03/assignment-3 */
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SEC("xdp_redirect_map")
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int xdp_redirect_map_func(struct xdp_md *ctx)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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struct hdr_cursor nh;
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struct ethhdr *eth;
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int eth_type;
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int action = XDP_PASS;
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unsigned char *dst;
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/* These keep track of the next header type and iterator pointer */
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nh.pos = data;
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/* Parse Ethernet and IP/IPv6 headers */
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eth_type = parse_ethhdr(&nh, data_end, &eth);
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if (eth_type == -1)
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goto out;
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/* Do we know where to redirect this packet? */
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dst = bpf_map_lookup_elem(&redirect_params, eth->h_source);
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if (!dst)
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goto out;
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/* Set a proper destination address */
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memcpy(eth->h_dest, dst, ETH_ALEN);
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action = bpf_redirect_map(&tx_port, 0, 0);
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out:
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return xdp_stats_record_action(ctx, action);
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}
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SEC("xdp_pass")
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int xdp_pass_func(struct xdp_md *ctx)
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{
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return xdp_stats_record_action(ctx, XDP_PASS);
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}
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char _license[] SEC("license") = "GPL";

‎packet04-tailgrow/xdp_prog_user.c‎

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/* SPDX-License-Identifier: GPL-2.0 */
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static const char *__doc__ = "XDP redirect helper\n"
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" - Allows to populate/query tx_port and redirect_params maps\n";
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <getopt.h>
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#include <stdbool.h>
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#include <locale.h>
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#include <unistd.h>
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#include <time.h>
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#include <bpf/bpf.h>
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#include <bpf/libbpf.h>
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#include <net/if.h>
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#include <linux/if_ether.h>
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#include <linux/if_link.h> /* depend on kernel-headers installed */
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#include "../common/common_params.h"
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#include "../common/common_user_bpf_xdp.h"
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#include "../common/common_libbpf.h"
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#include "../common/xdp_stats_kern_user.h"
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static const struct option_wrapper long_options[] = {
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{{"help", no_argument, NULL, 'h' },
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"Show help", false},
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{{"dev", required_argument, NULL, 'd' },
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"Operate on device <ifname>", "<ifname>", true},
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{{"redirect-dev", required_argument, NULL, 'r' },
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"Redirect to device <ifname>", "<ifname>", true},
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{{"src-mac", required_argument, NULL, 'L' },
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"Source MAC address of <dev>", "<mac>", true },
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{{"dest-mac", required_argument, NULL, 'R' },
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"Destination MAC address of <redirect-dev>", "<mac>", true },
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{{"quiet", no_argument, NULL, 'q' },
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"Quiet mode (no output)"},
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{{0, 0, NULL, 0 }, NULL, false}
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};
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static int parse_u8(char *str, unsigned char *x)
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{
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unsigned long z;
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z = strtoul(str, 0, 16);
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if (z > 0xff)
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return -1;
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if (x)
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*x = z;
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return 0;
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}
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static int parse_mac(char *str, unsigned char mac[ETH_ALEN])
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{
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if (parse_u8(str, &mac[0]) < 0)
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return -1;
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if (parse_u8(str + 3, &mac[1]) < 0)
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return -1;
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if (parse_u8(str + 6, &mac[2]) < 0)
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return -1;
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if (parse_u8(str + 9, &mac[3]) < 0)
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return -1;
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if (parse_u8(str + 12, &mac[4]) < 0)
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return -1;
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if (parse_u8(str + 15, &mac[5]) < 0)
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return -1;
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return 0;
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}
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static int write_iface_params(int map_fd, unsigned char *src, unsigned char *dest)
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{
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if (bpf_map_update_elem(map_fd, src, dest, 0) < 0) {
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fprintf(stderr,
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"WARN: Failed to update bpf map file: err(%d):%s\n",
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errno, strerror(errno));
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return -1;
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}
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printf("forward: %02x:%02x:%02x:%02x:%02x:%02x -> %02x:%02x:%02x:%02x:%02x:%02x\n",
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src[0], src[1], src[2], src[3], src[4], src[5],
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dest[0], dest[1], dest[2], dest[3], dest[4], dest[5]
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);
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return 0;
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}
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#ifndef PATH_MAX
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#define PATH_MAX 4096
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#endif
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const char *pin_basedir = "/sys/fs/bpf";
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int main(int argc, char **argv)
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{
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int i;
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int len;
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int map_fd;
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bool redirect_map;
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char pin_dir[PATH_MAX];
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unsigned char src[ETH_ALEN];
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unsigned char dest[ETH_ALEN];
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struct config cfg = {
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.ifindex = -1,
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.redirect_ifindex = -1,
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};
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/* Cmdline options can change progsec */
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parse_cmdline_args(argc, argv, long_options, &cfg, __doc__);
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redirect_map = (cfg.ifindex > 0) && (cfg.redirect_ifindex > 0);
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if (cfg.redirect_ifindex > 0 && cfg.ifindex == -1) {
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fprintf(stderr, "ERR: required option --dev missing\n\n");
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usage(argv[0], __doc__, long_options, (argc == 1));
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return EXIT_FAIL_OPTION;
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}
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len = snprintf(pin_dir, PATH_MAX, "%s/%s", pin_basedir, cfg.ifname);
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if (len < 0) {
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fprintf(stderr, "ERR: creating pin dirname\n");
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return EXIT_FAIL_OPTION;
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}
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if (parse_mac(cfg.src_mac, src) < 0) {
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fprintf(stderr, "ERR: can't parse mac address %s\n", cfg.src_mac);
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return EXIT_FAIL_OPTION;
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}
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if (parse_mac(cfg.dest_mac, dest) < 0) {
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fprintf(stderr, "ERR: can't parse mac address %s\n", cfg.dest_mac);
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return EXIT_FAIL_OPTION;
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}
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/* Open the tx_port map corresponding to the cfg.ifname interface */
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map_fd = open_bpf_map_file(pin_dir, "tx_port", NULL);
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if (map_fd < 0) {
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return EXIT_FAIL_BPF;
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}
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printf("map dir: %s\n", pin_dir);
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if (redirect_map) {
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/* setup a virtual port for the static redirect */
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i = 0;
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bpf_map_update_elem(map_fd, &i, &cfg.redirect_ifindex, 0);
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printf("redirect from ifnum=%d to ifnum=%d\n", cfg.ifindex, cfg.redirect_ifindex);
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/* Open the redirect_params map */
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map_fd = open_bpf_map_file(pin_dir, "redirect_params", NULL);
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if (map_fd < 0) {
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return EXIT_FAIL_BPF;
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}
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/* Setup the mapping containing MAC addresses */
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if (write_iface_params(map_fd, src, dest) < 0) {
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fprintf(stderr, "can't write iface params\n");
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return 1;
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}
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} else {
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/* setup 1-1 mapping for the dynamic router */
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for (i = 1; i < 256; ++i)
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bpf_map_update_elem(map_fd, &i, &i, 0);
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}
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return EXIT_OK;
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}

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