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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* em_cmp.c Simple comparison 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"
#include <linux/tc_ematch/tc_em_cmp.h>
extern struct ematch_util cmp_ematch_util;
static void cmp_print_usage(FILE *fd)
{
fprintf(fd,
"Usage: cmp(ALIGN at OFFSET [ ATTRS ] { eq | lt | gt } VALUE)\n" \
"where: ALIGN := { u8 | u16 | u32 }\n" \
" ATTRS := [ layer LAYER ] [ mask MASK ] [ trans ]\n" \
" LAYER := { link | network | transport | 0..%d }\n" \
"\n" \
"Example: cmp(u16 at 3 layer 2 mask 0xff00 gt 20)\n",
TCF_LAYER_MAX);
}
static int cmp_parse_eopt(struct nlmsghdr *n, struct tcf_ematch_hdr *hdr,
struct bstr *args)
{
struct bstr *a;
int align, opnd = 0;
unsigned long offset = 0, layer = TCF_LAYER_NETWORK, mask = 0, value = 0;
int offset_present = 0, value_present = 0;
struct tcf_em_cmp cmp = {};
#define PARSE_ERR(CARG, FMT, ARGS...) \
em_parse_error(EINVAL, args, CARG, &cmp_ematch_util, FMT, ##ARGS)
if (args == NULL)
return PARSE_ERR(args, "cmp: missing arguments");
if (!bstrcmp(args, "u8"))
align = TCF_EM_ALIGN_U8;
else if (!bstrcmp(args, "u16"))
align = TCF_EM_ALIGN_U16;
else if (!bstrcmp(args, "u32"))
align = TCF_EM_ALIGN_U32;
else
return PARSE_ERR(args, "cmp: invalid alignment");
for (a = bstr_next(args); a; a = bstr_next(a)) {
if (!bstrcmp(a, "at")) {
if (a->next == NULL)
return PARSE_ERR(a, "cmp: missing argument");
a = bstr_next(a);
offset = bstrtoul(a);
if (offset == ULONG_MAX)
return PARSE_ERR(a, "cmp: invalid offset, " \
"must be numeric");
offset_present = 1;
} else if (!bstrcmp(a, "layer")) {
if (a->next == NULL)
return PARSE_ERR(a, "cmp: missing argument");
a = bstr_next(a);
layer = parse_layer(a);
if (layer == INT_MAX) {
layer = bstrtoul(a);
if (layer == ULONG_MAX)
return PARSE_ERR(a, "cmp: invalid " \
"layer");
}
if (layer > TCF_LAYER_MAX)
return PARSE_ERR(a, "cmp: illegal layer, " \
"must be in 0..%d", TCF_LAYER_MAX);
} else if (!bstrcmp(a, "mask")) {
if (a->next == NULL)
return PARSE_ERR(a, "cmp: missing argument");
a = bstr_next(a);
mask = bstrtoul(a);
if (mask == ULONG_MAX)
return PARSE_ERR(a, "cmp: invalid mask");
} else if (!bstrcmp(a, "trans")) {
cmp.flags |= TCF_EM_CMP_TRANS;
} else if (!bstrcmp(a, "eq") || !bstrcmp(a, "gt") ||
!bstrcmp(a, "lt")) {
if (!bstrcmp(a, "eq"))
opnd = TCF_EM_OPND_EQ;
else if (!bstrcmp(a, "gt"))
opnd = TCF_EM_OPND_GT;
else if (!bstrcmp(a, "lt"))
opnd = TCF_EM_OPND_LT;
if (a->next == NULL)
return PARSE_ERR(a, "cmp: missing argument");
a = bstr_next(a);
value = bstrtoul(a);
if (value == ULONG_MAX)
return PARSE_ERR(a, "cmp: invalid value");
value_present = 1;
} else
return PARSE_ERR(a, "nbyte: unknown parameter");
}
if (offset_present == 0 || value_present == 0)
return PARSE_ERR(a, "cmp: offset and value required");
cmp.val = (__u32) value;
cmp.mask = (__u32) mask;
cmp.off = (__u16) offset;
cmp.align = (__u8) align;
cmp.layer = (__u8) layer;
cmp.opnd = (__u8) opnd;
addraw_l(n, MAX_MSG, hdr, sizeof(*hdr));
addraw_l(n, MAX_MSG, &cmp, sizeof(cmp));
#undef PARSE_ERR
return 0;
}
static int cmp_print_eopt(FILE *fd, struct tcf_ematch_hdr *hdr, void *data,
int data_len)
{
struct tcf_em_cmp *cmp = data;
if (data_len < sizeof(*cmp)) {
fprintf(stderr, "CMP header size mismatch\n");
return -1;
}
if (cmp->align == TCF_EM_ALIGN_U8)
fprintf(fd, "u8 ");
else if (cmp->align == TCF_EM_ALIGN_U16)
fprintf(fd, "u16 ");
else if (cmp->align == TCF_EM_ALIGN_U32)
fprintf(fd, "u32 ");
fprintf(fd, "at %d layer %d ", cmp->off, cmp->layer);
if (cmp->mask)
fprintf(fd, "mask 0x%x ", cmp->mask);
if (cmp->flags & TCF_EM_CMP_TRANS)
fprintf(fd, "trans ");
if (cmp->opnd == TCF_EM_OPND_EQ)
fprintf(fd, "eq ");
else if (cmp->opnd == TCF_EM_OPND_LT)
fprintf(fd, "lt ");
else if (cmp->opnd == TCF_EM_OPND_GT)
fprintf(fd, "gt ");
fprintf(fd, "%d", cmp->val);
return 0;
}
struct ematch_util cmp_ematch_util = {
.kind = "cmp",
.kind_num = TCF_EM_CMP,
.parse_eopt = cmp_parse_eopt,
.print_eopt = cmp_print_eopt,
.print_usage = cmp_print_usage
};
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