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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2022 Felix Fietkau <nbd@nbd.name>
*/
#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/resource.h>
#include <netinet/if_ether.h>
#include <netlink/msg.h>
#include <netlink/attr.h>
#include <netlink/socket.h>
#include <linux/rtnetlink.h>
#include <linux/pkt_cls.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#include "unetd.h"
static int unetd_bpf_pr(enum libbpf_print_level level, const char *format,
va_list args)
{
return vfprintf(stderr, format, args);
}
static void unetd_init_env(void)
{
struct rlimit limit = {
.rlim_cur = RLIM_INFINITY,
.rlim_max = RLIM_INFINITY,
};
setrlimit(RLIMIT_MEMLOCK, &limit);
}
static void
unetd_set_prog_mtu(struct bpf_object *obj, uint32_t mtu)
{
struct bpf_map *map = NULL;
while ((map = bpf_object__next_map(obj, map)) != NULL) {
if (!strstr(bpf_map__name(map), ".rodata"))
continue;
bpf_map__set_initial_value(map, &mtu, sizeof(mtu));
}
}
static int
unetd_attach_bpf_prog(int ifindex, int fd, bool egress)
{
DECLARE_LIBBPF_OPTS(bpf_tc_hook, hook,
.attach_point = egress ? BPF_TC_EGRESS : BPF_TC_INGRESS,
.ifindex = ifindex);
DECLARE_LIBBPF_OPTS(bpf_tc_opts, attach_tc,
.flags = BPF_TC_F_REPLACE,
.handle = 1,
.prog_fd = fd,
.priority = UNETD_MSS_PRIO_BASE);
bpf_tc_hook_create(&hook);
return bpf_tc_attach(&hook, &attach_tc);
}
int unetd_attach_mssfix(int ifindex, int mtu)
{
struct bpf_program *prog;
struct bpf_object *obj;
int prog_fd;
int ret = -1;
if (rtnl_init())
return -1;
unetd_init_env();
libbpf_set_print(unetd_bpf_pr);
obj = bpf_object__open_file(mssfix_path, NULL);
if (libbpf_get_error(obj)) {
perror("bpf_object__open_file");
goto out;
}
prog = bpf_object__find_program_by_name(obj, "mssfix");
if (!prog) {
perror("bpf_object__find_program_by_name");
goto out;
}
bpf_program__set_type(prog, BPF_PROG_TYPE_SCHED_CLS);
unetd_set_prog_mtu(obj, mtu);
if (bpf_object__load(obj)) {
perror("bpf_object__load");
goto out;
}
prog_fd = bpf_program__fd(prog);
unetd_attach_bpf_prog(ifindex, prog_fd, true);
unetd_attach_bpf_prog(ifindex, prog_fd, false);
ret = 0;
out:
bpf_object__close(obj);
return ret;
}
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