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#include <stddef.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <netinet/in.h>
#include <netinet/ip6.h>
#include <netinet/tcp.h>
#include <utils.h>
#include <headers.h>
#include <expression.h>
#include <tcpopt.h>
static const struct proto_hdr_template tcpopt_unknown_template =
PROTO_HDR_TEMPLATE("unknown", &invalid_type, BYTEORDER_INVALID, 0, 0);
#define PHT(__token, __offset, __len) \
PROTO_HDR_TEMPLATE(__token, &integer_type, BYTEORDER_BIG_ENDIAN, \
__offset, __len)
static const struct exthdr_desc tcpopt_eol = {
.name = "eol",
.type = TCPOPT_KIND_EOL,
.templates = {
[TCPOPT_COMMON_KIND] = PHT("kind", 0, 8),
},
};
static const struct exthdr_desc tcpopt_nop = {
.name = "nop",
.type = TCPOPT_KIND_NOP,
.templates = {
[TCPOPT_COMMON_KIND] = PHT("kind", 0, 8),
},
};
static const struct exthdr_desc tcptopt_maxseg = {
.name = "maxseg",
.type = TCPOPT_KIND_MAXSEG,
.templates = {
[TCPOPT_MAXSEG_KIND] = PHT("kind", 0, 8),
[TCPOPT_MAXSEG_LENGTH] = PHT("length", 8, 8),
[TCPOPT_MAXSEG_SIZE] = PHT("size", 16, 16),
},
};
static const struct exthdr_desc tcpopt_window = {
.name = "window",
.type = TCPOPT_KIND_WINDOW,
.templates = {
[TCPOPT_WINDOW_KIND] = PHT("kind", 0, 8),
[TCPOPT_WINDOW_LENGTH] = PHT("length", 8, 8),
[TCPOPT_WINDOW_COUNT] = PHT("count", 16, 8),
},
};
static const struct exthdr_desc tcpopt_sack_permitted = {
.name = "sack-perm",
.type = TCPOPT_KIND_SACK_PERMITTED,
.templates = {
[TCPOPT_COMMON_KIND] = PHT("kind", 0, 8),
[TCPOPT_COMMON_LENGTH] = PHT("length", 8, 8),
},
};
static const struct exthdr_desc tcpopt_sack = {
.name = "sack",
.type = TCPOPT_KIND_SACK,
.templates = {
[TCPOPT_SACK_KIND] = PHT("kind", 0, 8),
[TCPOPT_SACK_LENGTH] = PHT("length", 8, 8),
[TCPOPT_SACK_LEFT] = PHT("left", 16, 32),
[TCPOPT_SACK_RIGHT] = PHT("right", 48, 32),
[TCPOPT_SACK_LEFT1] = PHT("left", 80, 32),
[TCPOPT_SACK_RIGHT1] = PHT("right", 112, 32),
[TCPOPT_SACK_LEFT2] = PHT("left", 144, 32),
[TCPOPT_SACK_RIGHT2] = PHT("right", 176, 32),
[TCPOPT_SACK_LEFT3] = PHT("left", 208, 32),
[TCPOPT_SACK_RIGHT3] = PHT("right", 240, 32),
},
};
static const struct exthdr_desc tcpopt_timestamp = {
.name = "timestamp",
.type = TCPOPT_KIND_TIMESTAMP,
.templates = {
[TCPOPT_TS_KIND] = PHT("kind", 0, 8),
[TCPOPT_TS_LENGTH] = PHT("length", 8, 8),
[TCPOPT_TS_TSVAL] = PHT("tsval", 16, 32),
[TCPOPT_TS_TSECR] = PHT("tsecr", 48, 32),
},
};
#undef PHT
const struct exthdr_desc *tcpopt_protocols[] = {
[TCPOPT_KIND_EOL] = &tcpopt_eol,
[TCPOPT_KIND_NOP] = &tcpopt_nop,
[TCPOPT_KIND_MAXSEG] = &tcptopt_maxseg,
[TCPOPT_KIND_WINDOW] = &tcpopt_window,
[TCPOPT_KIND_SACK_PERMITTED] = &tcpopt_sack_permitted,
[TCPOPT_KIND_SACK] = &tcpopt_sack,
[TCPOPT_KIND_TIMESTAMP] = &tcpopt_timestamp,
};
/**
* tcpopt_expr_alloc - allocate tcp option extension expression
*
* @loc: location from parser
* @kind: raw tcp option value to find in packet
* @field: highlevel field to find in the option if @kind is present in packet
*
* Allocate a new tcp option expression.
* @kind is the raw option value to find in the packet.
* Exception: SACK may use extra OOB data that is mangled here.
*
* @field is the optional field to extract from the @type option.
*/
struct expr *tcpopt_expr_alloc(const struct location *loc,
unsigned int kind,
unsigned int field)
{
const struct proto_hdr_template *tmpl;
const struct exthdr_desc *desc = NULL;
struct expr *expr;
switch (kind) {
case TCPOPT_KIND_SACK1:
kind = TCPOPT_KIND_SACK;
if (field == TCPOPT_SACK_LEFT)
field = TCPOPT_SACK_LEFT1;
else if (field == TCPOPT_SACK_RIGHT)
field = TCPOPT_SACK_RIGHT1;
break;
case TCPOPT_KIND_SACK2:
kind = TCPOPT_KIND_SACK;
if (field == TCPOPT_SACK_LEFT)
field = TCPOPT_SACK_LEFT2;
else if (field == TCPOPT_SACK_RIGHT)
field = TCPOPT_SACK_RIGHT2;
break;
case TCPOPT_KIND_SACK3:
kind = TCPOPT_KIND_SACK;
if (field == TCPOPT_SACK_LEFT)
field = TCPOPT_SACK_LEFT3;
else if (field == TCPOPT_SACK_RIGHT)
field = TCPOPT_SACK_RIGHT3;
break;
}
if (kind < array_size(tcpopt_protocols))
desc = tcpopt_protocols[kind];
if (!desc) {
if (field != TCPOPT_COMMON_KIND || kind > 255)
return NULL;
expr = expr_alloc(loc, EXPR_EXTHDR, &integer_type,
BYTEORDER_BIG_ENDIAN, 8);
desc = tcpopt_protocols[TCPOPT_NOP];
tmpl = &desc->templates[field];
expr->exthdr.desc = desc;
expr->exthdr.tmpl = tmpl;
expr->exthdr.op = NFT_EXTHDR_OP_TCPOPT;
expr->exthdr.raw_type = kind;
return expr;
}
tmpl = &desc->templates[field];
if (!tmpl)
return NULL;
expr = expr_alloc(loc, EXPR_EXTHDR, tmpl->dtype,
BYTEORDER_BIG_ENDIAN, tmpl->len);
expr->exthdr.desc = desc;
expr->exthdr.tmpl = tmpl;
expr->exthdr.op = NFT_EXTHDR_OP_TCPOPT;
expr->exthdr.raw_type = desc->type;
expr->exthdr.offset = tmpl->offset;
return expr;
}
void tcpopt_init_raw(struct expr *expr, uint8_t type, unsigned int off,
unsigned int len, uint32_t flags)
{
const struct proto_hdr_template *tmpl;
unsigned int i;
assert(expr->etype == EXPR_EXTHDR);
expr->len = len;
expr->exthdr.flags = flags;
expr->exthdr.offset = off;
expr->exthdr.op = NFT_EXTHDR_OP_TCPOPT;
if (flags & NFT_EXTHDR_F_PRESENT)
datatype_set(expr, &boolean_type);
else
datatype_set(expr, &integer_type);
if (type >= array_size(tcpopt_protocols))
return;
expr->exthdr.desc = tcpopt_protocols[type];
expr->exthdr.flags = flags;
assert(expr->exthdr.desc != NULL);
for (i = 0; i < array_size(expr->exthdr.desc->templates); ++i) {
tmpl = &expr->exthdr.desc->templates[i];
if (tmpl->offset != off || tmpl->len != len)
continue;
if ((flags & NFT_EXTHDR_F_PRESENT) == 0)
datatype_set(expr, tmpl->dtype);
expr->exthdr.tmpl = tmpl;
break;
}
}
bool tcpopt_find_template(struct expr *expr, const struct expr *mask,
unsigned int *shift)
{
if (expr->exthdr.tmpl != &tcpopt_unknown_template)
return false;
tcpopt_init_raw(expr, expr->exthdr.desc->type, expr->exthdr.offset,
expr->len, 0);
if (expr->exthdr.tmpl == &tcpopt_unknown_template)
return false;
return true;
}
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