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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_EOL,
.templates = {
[TCPOPTHDR_FIELD_KIND] = PHT("kind", 0, 8),
},
};
static const struct exthdr_desc tcpopt_nop = {
.name = "noop",
.type = TCPOPT_NOP,
.templates = {
[TCPOPTHDR_FIELD_KIND] = PHT("kind", 0, 8),
},
};
static const struct exthdr_desc tcptopt_maxseg = {
.name = "maxseg",
.type = TCPOPT_MAXSEG,
.templates = {
[TCPOPTHDR_FIELD_KIND] = PHT("kind", 0, 8),
[TCPOPTHDR_FIELD_LENGTH] = PHT("length", 8, 8),
[TCPOPTHDR_FIELD_SIZE] = PHT("size", 16, 16),
},
};
static const struct exthdr_desc tcpopt_window = {
.name = "window",
.type = TCPOPT_WINDOW,
.templates = {
[TCPOPTHDR_FIELD_KIND] = PHT("kind", 0, 8),
[TCPOPTHDR_FIELD_LENGTH] = PHT("length", 8, 8),
[TCPOPTHDR_FIELD_COUNT] = PHT("count", 16, 8),
},
};
static const struct exthdr_desc tcpopt_sack_permitted = {
.name = "sack-permitted",
.type = TCPOPT_SACK_PERMITTED,
.templates = {
[TCPOPTHDR_FIELD_KIND] = PHT("kind", 0, 8),
[TCPOPTHDR_FIELD_LENGTH] = PHT("length", 8, 8),
},
};
static const struct exthdr_desc tcpopt_sack = {
.name = "sack",
.type = TCPOPT_SACK,
.templates = {
[TCPOPTHDR_FIELD_KIND] = PHT("kind", 0, 8),
[TCPOPTHDR_FIELD_LENGTH] = PHT("length", 8, 8),
[TCPOPTHDR_FIELD_LEFT] = PHT("left", 16, 32),
[TCPOPTHDR_FIELD_RIGHT] = PHT("right", 48, 32),
},
};
static const struct exthdr_desc tcpopt_timestamp = {
.name = "timestamp",
.type = TCPOPT_TIMESTAMP,
.templates = {
[TCPOPTHDR_FIELD_KIND] = PHT("kind", 0, 8),
[TCPOPTHDR_FIELD_LENGTH] = PHT("length", 8, 8),
[TCPOPTHDR_FIELD_TSVAL] = PHT("tsval", 16, 32),
[TCPOPTHDR_FIELD_TSECR] = PHT("tsecr", 48, 32),
},
};
#undef PHT
#define TCPOPT_OBSOLETE ((struct exthdr_desc *)NULL)
#define TCPOPT_ECHO 6
#define TCPOPT_ECHO_REPLY 7
static const struct exthdr_desc *tcpopt_protocols[] = {
[TCPOPT_EOL] = &tcpopt_eol,
[TCPOPT_NOP] = &tcpopt_nop,
[TCPOPT_MAXSEG] = &tcptopt_maxseg,
[TCPOPT_WINDOW] = &tcpopt_window,
[TCPOPT_SACK_PERMITTED] = &tcpopt_sack_permitted,
[TCPOPT_SACK] = &tcpopt_sack,
[TCPOPT_ECHO] = TCPOPT_OBSOLETE,
[TCPOPT_ECHO_REPLY] = TCPOPT_OBSOLETE,
[TCPOPT_TIMESTAMP] = &tcpopt_timestamp,
};
static unsigned int calc_offset(const struct exthdr_desc *desc,
const struct proto_hdr_template *tmpl,
unsigned int num)
{
if (!desc || tmpl == &tcpopt_unknown_template)
return 0;
switch (desc->type) {
case TCPOPT_SACK:
/* Make sure, offset calculations only apply to left and right
* fields
*/
return (tmpl->offset < 16) ? 0 : num * 64;
default:
return 0;
}
}
static unsigned int calc_offset_reverse(const struct exthdr_desc *desc,
const struct proto_hdr_template *tmpl,
unsigned int offset)
{
if (!desc || tmpl == &tcpopt_unknown_template)
return offset;
switch (desc->type) {
case TCPOPT_SACK:
/* We can safely ignore the first left/right field */
return offset < 80 ? offset : (offset % 64);
default:
return offset;
}
}
static const struct exthdr_desc *tcpopthdr_protocols[] = {
[TCPOPTHDR_EOL] = &tcpopt_eol,
[TCPOPTHDR_NOOP] = &tcpopt_nop,
[TCPOPTHDR_MAXSEG] = &tcptopt_maxseg,
[TCPOPTHDR_WINDOW] = &tcpopt_window,
[TCPOPTHDR_SACK_PERMITTED] = &tcpopt_sack_permitted,
[TCPOPTHDR_SACK0] = &tcpopt_sack,
[TCPOPTHDR_SACK1] = &tcpopt_sack,
[TCPOPTHDR_SACK2] = &tcpopt_sack,
[TCPOPTHDR_SACK3] = &tcpopt_sack,
[TCPOPTHDR_ECHO] = TCPOPT_OBSOLETE,
[TCPOPTHDR_ECHO_REPLY] = TCPOPT_OBSOLETE,
[TCPOPTHDR_TIMESTAMP] = &tcpopt_timestamp,
};
static uint8_t tcpopt_optnum[] = {
[TCPOPTHDR_SACK0] = 0,
[TCPOPTHDR_SACK1] = 1,
[TCPOPTHDR_SACK2] = 2,
[TCPOPTHDR_SACK3] = 3,
};
static uint8_t tcpopt_find_optnum(uint8_t optnum)
{
if (optnum > TCPOPTHDR_SACK3)
return 0;
return tcpopt_optnum[optnum];
}
struct expr *tcpopt_expr_alloc(const struct location *loc, uint8_t type,
uint8_t field)
{
const struct proto_hdr_template *tmpl;
const struct exthdr_desc *desc;
struct expr *expr;
uint8_t optnum;
desc = tcpopthdr_protocols[type];
tmpl = &desc->templates[field];
if (!tmpl)
return NULL;
optnum = tcpopt_find_optnum(type);
expr = expr_alloc(loc, &exthdr_expr_ops, tmpl->dtype,
BYTEORDER_BIG_ENDIAN, tmpl->len);
expr->exthdr.desc = desc;
expr->exthdr.tmpl = tmpl;
expr->exthdr.op = NFT_EXTHDR_OP_TCPOPT;
expr->exthdr.offset = calc_offset(desc, tmpl, optnum);
return expr;
}
void tcpopt_init_raw(struct expr *expr, uint8_t type, unsigned int offset,
unsigned int len, uint32_t flags)
{
const struct proto_hdr_template *tmpl;
unsigned int i, off;
assert(expr->ops->type == EXPR_EXTHDR);
expr->len = len;
expr->exthdr.flags = flags;
expr->exthdr.offset = offset;
assert(type < array_size(tcpopt_protocols));
expr->exthdr.desc = tcpopt_protocols[type];
expr->exthdr.flags = flags;
assert(expr->exthdr.desc != TCPOPT_OBSOLETE);
for (i = 0; i < array_size(expr->exthdr.desc->templates); ++i) {
tmpl = &expr->exthdr.desc->templates[i];
/* We have to reverse calculate the offset for the sack options
* at this point
*/
off = calc_offset_reverse(expr->exthdr.desc, tmpl, offset);
if (tmpl->offset != off || tmpl->len != len)
continue;
if (flags & NFT_EXTHDR_F_PRESENT)
expr->dtype = &boolean_type;
else
expr->dtype = tmpl->dtype;
expr->exthdr.tmpl = tmpl;
expr->exthdr.op = NFT_EXTHDR_OP_TCPOPT;
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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