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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* em_u32.c U32 Ematch
*
* Authors: Thomas Graf <tgraf@suug.ch>
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <errno.h>
#include "m_ematch.h"
extern struct ematch_util u32_ematch_util;
static void u32_print_usage(FILE *fd)
{
fprintf(fd,
"Usage: u32(ALIGN VALUE MASK at [ nexthdr+ ] OFFSET)\n" \
"where: ALIGN := { u8 | u16 | u32 }\n" \
"\n" \
"Example: u32(u16 0x1122 0xffff at nexthdr+4)\n");
}
static int u32_parse_eopt(struct nlmsghdr *n, struct tcf_ematch_hdr *hdr,
struct bstr *args)
{
struct bstr *a;
int align, nh_len;
unsigned long key, mask, offmask = 0, offset;
struct tc_u32_key u_key = {};
#define PARSE_ERR(CARG, FMT, ARGS...) \
em_parse_error(EINVAL, args, CARG, &u32_ematch_util, FMT, ##ARGS)
if (args == NULL)
return PARSE_ERR(args, "u32: missing arguments");
if (!bstrcmp(args, "u8"))
align = 1;
else if (!bstrcmp(args, "u16"))
align = 2;
else if (!bstrcmp(args, "u32"))
align = 4;
else
return PARSE_ERR(args, "u32: invalid alignment");
a = bstr_next(args);
if (a == NULL)
return PARSE_ERR(a, "u32: missing key");
key = bstrtoul(a);
if (key == ULONG_MAX)
return PARSE_ERR(a, "u32: invalid key, must be numeric");
a = bstr_next(a);
if (a == NULL)
return PARSE_ERR(a, "u32: missing mask");
mask = bstrtoul(a);
if (mask == ULONG_MAX)
return PARSE_ERR(a, "u32: invalid mask, must be numeric");
a = bstr_next(a);
if (a == NULL || bstrcmp(a, "at") != 0)
return PARSE_ERR(a, "u32: missing \"at\"");
a = bstr_next(a);
if (a == NULL)
return PARSE_ERR(a, "u32: missing offset");
nh_len = strlen("nexthdr+");
if (a->len > nh_len && !memcmp(a->data, "nexthdr+", nh_len)) {
char buf[a->len - nh_len + 1];
offmask = -1;
strncpy(buf, a->data + nh_len, a->len - nh_len + 1);
offset = strtoul(buf, NULL, 0);
} else if (!bstrcmp(a, "nexthdr+")) {
a = bstr_next(a);
if (a == NULL)
return PARSE_ERR(a, "u32: missing offset");
offset = bstrtoul(a);
} else
offset = bstrtoul(a);
if (offset == ULONG_MAX)
return PARSE_ERR(a, "u32: invalid offset");
if (a->next)
return PARSE_ERR(a->next, "u32: unexpected trailer");
switch (align) {
case 1:
if (key > 0xFF)
return PARSE_ERR(a, "Illegal key (>0xFF)");
if (mask > 0xFF)
return PARSE_ERR(a, "Illegal mask (>0xFF)");
key <<= 24 - ((offset & 3) * 8);
mask <<= 24 - ((offset & 3) * 8);
offset &= ~3;
break;
case 2:
if (key > 0xFFFF)
return PARSE_ERR(a, "Illegal key (>0xFFFF)");
if (mask > 0xFFFF)
return PARSE_ERR(a, "Illegal mask (>0xFFFF)");
if ((offset & 3) == 0) {
key <<= 16;
mask <<= 16;
}
offset &= ~3;
break;
}
key = htonl(key);
mask = htonl(mask);
if (offset % 4)
return PARSE_ERR(a, "u32: invalid offset alignment, " \
"must be aligned to 4.");
key &= mask;
u_key.mask = mask;
u_key.val = key;
u_key.off = offset;
u_key.offmask = offmask;
addraw_l(n, MAX_MSG, hdr, sizeof(*hdr));
addraw_l(n, MAX_MSG, &u_key, sizeof(u_key));
#undef PARSE_ERR
return 0;
}
static int u32_print_eopt(FILE *fd, struct tcf_ematch_hdr *hdr, void *data,
int data_len)
{
struct tc_u32_key *u_key = data;
if (data_len < sizeof(*u_key)) {
fprintf(stderr, "U32 header size mismatch\n");
return -1;
}
fprintf(fd, "%08x/%08x at %s%d",
(unsigned int) ntohl(u_key->val),
(unsigned int) ntohl(u_key->mask),
u_key->offmask ? "nexthdr+" : "",
u_key->off);
return 0;
}
struct ematch_util u32_ematch_util = {
.kind = "u32",
.kind_num = TCF_EM_U32,
.parse_eopt = u32_parse_eopt,
.print_eopt = u32_print_eopt,
.print_usage = u32_print_usage
};
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