From 05e59e5fb0064c97a1c10921ecd549f2d4a58565 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 09 Oct 2024 06:14:40 +0000
Subject: [PATCH] add REDIRECT
---
kernel/samples/bpf/xdp_adjust_tail_user.c | 86 +++++++++++++++++++++++++++++++++---------
1 files changed, 67 insertions(+), 19 deletions(-)
diff --git a/kernel/samples/bpf/xdp_adjust_tail_user.c b/kernel/samples/bpf/xdp_adjust_tail_user.c
index 3042ce3..ba482dc 100644
--- a/kernel/samples/bpf/xdp_adjust_tail_user.c
+++ b/kernel/samples/bpf/xdp_adjust_tail_user.c
@@ -13,23 +13,38 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <net/if.h>
#include <sys/resource.h>
#include <arpa/inet.h>
#include <netinet/ether.h>
#include <unistd.h>
#include <time.h>
-#include "bpf/bpf.h"
-#include "bpf/libbpf.h"
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
#define STATS_INTERVAL_S 2U
+#define MAX_PCKT_SIZE 600
static int ifindex = -1;
-static __u32 xdp_flags;
+static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
+static __u32 prog_id;
static void int_exit(int sig)
{
- if (ifindex > -1)
- bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
+ __u32 curr_prog_id = 0;
+
+ if (ifindex > -1) {
+ if (bpf_get_link_xdp_id(ifindex, &curr_prog_id, xdp_flags)) {
+ printf("bpf_get_link_xdp_id failed\n");
+ exit(1);
+ }
+ if (prog_id == curr_prog_id)
+ bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
+ else if (!curr_prog_id)
+ printf("couldn't find a prog id on a given iface\n");
+ else
+ printf("program on interface changed, not removing\n");
+ }
exit(0);
}
@@ -56,10 +71,12 @@
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(" -i <ifname|ifindex> Interface\n");
printf(" -T <stop-after-X-seconds> Default: 0 (forever)\n");
+ printf(" -P <MAX_PCKT_SIZE> Default: %u\n", MAX_PCKT_SIZE);
printf(" -S use skb-mode\n");
printf(" -N enforce native mode\n");
+ printf(" -F force loading prog\n");
printf(" -h Display this help\n");
}
@@ -70,12 +87,16 @@
.prog_type = BPF_PROG_TYPE_XDP,
};
unsigned char opt_flags[256] = {};
+ const char *optstr = "i:T:P:SNFh";
+ struct bpf_prog_info info = {};
+ __u32 info_len = sizeof(info);
unsigned int kill_after_s = 0;
- const char *optstr = "i:T:SNh";
int i, prog_fd, map_fd, opt;
struct bpf_object *obj;
- struct bpf_map *map;
+ __u32 max_pckt_size = 0;
+ __u32 key = 0;
char filename[256];
+ int err;
for (i = 0; i < strlen(optstr); i++)
if (optstr[i] != 'h' && 'a' <= optstr[i] && optstr[i] <= 'z')
@@ -85,16 +106,24 @@
switch (opt) {
case 'i':
- ifindex = atoi(optarg);
+ ifindex = if_nametoindex(optarg);
+ if (!ifindex)
+ ifindex = atoi(optarg);
break;
case 'T':
kill_after_s = atoi(optarg);
+ break;
+ case 'P':
+ max_pckt_size = atoi(optarg);
break;
case 'S':
xdp_flags |= XDP_FLAGS_SKB_MODE;
break;
case 'N':
- xdp_flags |= XDP_FLAGS_DRV_MODE;
+ /* default, set below */
+ break;
+ case 'F':
+ xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
break;
default:
usage(argv[0]);
@@ -102,6 +131,9 @@
}
opt_flags[opt] = 0;
}
+
+ if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
+ xdp_flags |= XDP_FLAGS_DRV_MODE;
for (i = 0; i < strlen(optstr); i++) {
if (opt_flags[(unsigned int)optstr[i]]) {
@@ -116,21 +148,31 @@
return 1;
}
+ if (!ifindex) {
+ fprintf(stderr, "Invalid ifname\n");
+ return 1;
+ }
+
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
prog_load_attr.file = filename;
if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
return 1;
- map = bpf_map__next(NULL, obj);
- if (!map) {
- printf("finding a map in obj file failed\n");
- return 1;
+ /* static global var 'max_pcktsz' is accessible from .data section */
+ if (max_pckt_size) {
+ map_fd = bpf_object__find_map_fd_by_name(obj, "xdp_adju.data");
+ if (map_fd < 0) {
+ printf("finding a max_pcktsz map in obj file failed\n");
+ return 1;
+ }
+ bpf_map_update_elem(map_fd, &key, &max_pckt_size, BPF_ANY);
}
- map_fd = bpf_map__fd(map);
- if (!prog_fd) {
- printf("load_bpf_file: %s\n", strerror(errno));
+ /* fetch icmpcnt map */
+ map_fd = bpf_object__find_map_fd_by_name(obj, "icmpcnt");
+ if (map_fd < 0) {
+ printf("finding a icmpcnt map in obj file failed\n");
return 1;
}
@@ -142,9 +184,15 @@
return 1;
}
- poll_stats(map_fd, kill_after_s);
+ err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
+ if (err) {
+ printf("can't get prog info - %s\n", strerror(errno));
+ return 1;
+ }
+ prog_id = info.id;
- bpf_set_link_xdp_fd(ifindex, -1, xdp_flags);
+ poll_stats(map_fd, kill_after_s);
+ int_exit(0);
return 0;
}
--
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