blob: 48635a70629bf6fd1dbb3e8ed7dba4e85b7569f7 [file] [log] [blame]
/*
* f_bpf.c BPF-based Classifier
*
* This program is free software; you can distribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Authors: Daniel Borkmann <dborkman@redhat.com>
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <stdbool.h>
#include <errno.h>
#include <limits.h>
#include <linux/filter.h>
#include <linux/if.h>
#include "utils.h"
#include "tc_util.h"
static void explain(void)
{
fprintf(stderr, "Usage: ... bpf ...\n");
fprintf(stderr, "\n");
fprintf(stderr, " [inline]: run bytecode BPF_BYTECODE\n");
fprintf(stderr, " [from file]: run bytecode-file FILE\n");
fprintf(stderr, "\n");
fprintf(stderr, " [ action ACTION_SPEC ]\n");
fprintf(stderr, " [ classid CLASSID ]\n");
fprintf(stderr, "\n");
fprintf(stderr, "Where BPF_BYTECODE := \'s,c t f k,c t f k,c t f k,...\'\n");
fprintf(stderr, " c,t,f,k and s are decimals; s denotes number of 4-tuples\n");
fprintf(stderr, "Where FILE points to a file containing the BPF_BYTECODE string\n");
fprintf(stderr, "\nACTION_SPEC := ... look at individual actions\n");
fprintf(stderr, "NOTE: CLASSID is parsed as hexadecimal input.\n");
}
static int bpf_parse_string(char *arg, bool from_file, __u16 *bpf_len,
char **bpf_string, bool *need_release,
const char separator)
{
char sp;
if (from_file) {
size_t tmp_len, op_len = sizeof("65535 255 255 4294967295,");
char *tmp_string;
FILE *fp;
tmp_len = sizeof("4096,") + BPF_MAXINSNS * op_len;
tmp_string = malloc(tmp_len);
if (tmp_string == NULL)
return -ENOMEM;
memset(tmp_string, 0, tmp_len);
fp = fopen(arg, "r");
if (fp == NULL) {
perror("Cannot fopen");
free(tmp_string);
return -ENOENT;
}
if (!fgets(tmp_string, tmp_len, fp)) {
free(tmp_string);
fclose(fp);
return -EIO;
}
fclose(fp);
*need_release = true;
*bpf_string = tmp_string;
} else {
*need_release = false;
*bpf_string = arg;
}
if (sscanf(*bpf_string, "%hu%c", bpf_len, &sp) != 2 ||
sp != separator) {
if (*need_release)
free(*bpf_string);
return -EINVAL;
}
return 0;
}
static int bpf_parse_ops(int argc, char **argv, struct nlmsghdr *n,
bool from_file)
{
char *bpf_string, *token, separator = ',';
struct sock_filter bpf_ops[BPF_MAXINSNS];
int ret = 0, i = 0;
bool need_release;
__u16 bpf_len = 0;
if (argc < 1)
return -EINVAL;
if (bpf_parse_string(argv[0], from_file, &bpf_len, &bpf_string,
&need_release, separator))
return -EINVAL;
if (bpf_len == 0 || bpf_len > BPF_MAXINSNS) {
ret = -EINVAL;
goto out;
}
token = bpf_string;
while ((token = strchr(token, separator)) && (++token)[0]) {
if (i >= bpf_len) {
fprintf(stderr, "Real program length exceeds encoded "
"length parameter!\n");
ret = -EINVAL;
goto out;
}
if (sscanf(token, "%hu %hhu %hhu %u,",
&bpf_ops[i].code, &bpf_ops[i].jt,
&bpf_ops[i].jf, &bpf_ops[i].k) != 4) {
fprintf(stderr, "Error at instruction %d!\n", i);
ret = -EINVAL;
goto out;
}
i++;
}
if (i != bpf_len) {
fprintf(stderr, "Parsed program length is less than encoded"
"length parameter!\n");
ret = -EINVAL;
goto out;
}
addattr_l(n, MAX_MSG, TCA_BPF_OPS_LEN, &bpf_len, sizeof(bpf_len));
addattr_l(n, MAX_MSG, TCA_BPF_OPS, &bpf_ops,
bpf_len * sizeof(struct sock_filter));
out:
if (need_release)
free(bpf_string);
return ret;
}
static void bpf_print_ops(FILE *f, struct rtattr *bpf_ops, __u16 len)
{
struct sock_filter *ops = (struct sock_filter *) RTA_DATA(bpf_ops);
int i;
if (len == 0)
return;
fprintf(f, "bytecode \'%u,", len);
for (i = 0; i < len - 1; i++)
fprintf(f, "%hu %hhu %hhu %u,", ops[i].code, ops[i].jt,
ops[i].jf, ops[i].k);
fprintf(f, "%hu %hhu %hhu %u\'\n", ops[i].code, ops[i].jt,
ops[i].jf, ops[i].k);
}
static int bpf_parse_opt(struct filter_util *qu, char *handle,
int argc, char **argv, struct nlmsghdr *n)
{
struct tcmsg *t = NLMSG_DATA(n);
struct rtattr *tail;
long h = 0;
if (argc == 0)
return 0;
if (handle) {
h = strtol(handle, NULL, 0);
if (h == LONG_MIN || h == LONG_MAX) {
fprintf(stderr, "Illegal handle \"%s\", must be "
"numeric.\n", handle);
return -1;
}
}
t->tcm_handle = h;
tail = (struct rtattr*)(((void*)n)+NLMSG_ALIGN(n->nlmsg_len));
addattr_l(n, MAX_MSG, TCA_OPTIONS, NULL, 0);
while (argc > 0) {
if (matches(*argv, "run") == 0) {
bool from_file;
NEXT_ARG();
if (strcmp(*argv, "bytecode-file") == 0) {
from_file = true;
} else if (strcmp(*argv, "bytecode") == 0) {
from_file = false;
} else {
fprintf(stderr, "What is \"%s\"?\n", *argv);
explain();
return -1;
}
NEXT_ARG();
if (bpf_parse_ops(argc, argv, n, from_file)) {
fprintf(stderr, "Illegal \"bytecode\"\n");
return -1;
}
} else if (matches(*argv, "classid") == 0 ||
strcmp(*argv, "flowid") == 0) {
unsigned handle;
NEXT_ARG();
if (get_tc_classid(&handle, *argv)) {
fprintf(stderr, "Illegal \"classid\"\n");
return -1;
}
addattr_l(n, MAX_MSG, TCA_BPF_CLASSID, &handle, 4);
} else if (matches(*argv, "action") == 0) {
NEXT_ARG();
if (parse_action(&argc, &argv, TCA_BPF_ACT, n)) {
fprintf(stderr, "Illegal \"action\"\n");
return -1;
}
continue;
} else if (matches(*argv, "police") == 0) {
NEXT_ARG();
if (parse_police(&argc, &argv, TCA_BPF_POLICE, n)) {
fprintf(stderr, "Illegal \"police\"\n");
return -1;
}
continue;
} else if (strcmp(*argv, "help") == 0) {
explain();
return -1;
} else {
fprintf(stderr, "What is \"%s\"?\n", *argv);
explain();
return -1;
}
argc--; argv++;
}
tail->rta_len = (((void*)n)+n->nlmsg_len) - (void*)tail;
return 0;
}
static int bpf_print_opt(struct filter_util *qu, FILE *f,
struct rtattr *opt, __u32 handle)
{
struct rtattr *tb[TCA_BPF_MAX + 1];
if (opt == NULL)
return 0;
parse_rtattr_nested(tb, TCA_BPF_MAX, opt);
if (handle)
fprintf(f, "handle 0x%x ", handle);
if (tb[TCA_BPF_CLASSID]) {
SPRINT_BUF(b1);
fprintf(f, "flowid %s ",
sprint_tc_classid(rta_getattr_u32(tb[TCA_BPF_CLASSID]), b1));
}
if (tb[TCA_BPF_OPS] && tb[TCA_BPF_OPS_LEN])
bpf_print_ops(f, tb[TCA_BPF_OPS],
rta_getattr_u16(tb[TCA_BPF_OPS_LEN]));
if (tb[TCA_BPF_POLICE]) {
fprintf(f, "\n");
tc_print_police(f, tb[TCA_BPF_POLICE]);
}
if (tb[TCA_BPF_ACT]) {
tc_print_action(f, tb[TCA_BPF_ACT]);
}
return 0;
}
struct filter_util bpf_filter_util = {
.id = "bpf",
.parse_fopt = bpf_parse_opt,
.print_fopt = bpf_print_opt,
};