/*
* m_pedit.c generic packet editor actions module
*
* 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: J Hadi Salim (hadi@cyberus.ca)
*
* TODO:
* 1) Big endian broken in some spots
* 2) A lot of this stuff was added on the fly; get a big double-double
* and clean it up at some point.
*
*/
#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 <dlfcn.h>
#include "utils.h"
#include "tc_util.h"
#include "m_pedit.h"
#include "rt_names.h"
static struct m_pedit_util *pedit_list;
static int pedit_debug;
static void explain(void)
{
fprintf(stderr,
"Usage: ... pedit munge [ex] <MUNGE> [CONTROL]\n"
"Where: MUNGE := <RAW>|<LAYERED>\n"
"\t<RAW>:= <OFFSETC>[ATC]<CMD>\n \t\tOFFSETC:= offset <offval> <u8|u16|u32>\n"
"\t\tATC:= at <atval> offmask <maskval> shift <shiftval>\n"
"\t\tNOTE: offval is byte offset, must be multiple of 4\n"
"\t\tNOTE: maskval is a 32 bit hex number\n \t\tNOTE: shiftval is a shift value\n"
"\t\tCMD:= clear | invert | set <setval>| add <addval> | retain\n"
"\t<LAYERED>:= ip <ipdata> | ip6 <ip6data>\n"
" \t\t| udp <udpdata> | tcp <tcpdata> | icmp <icmpdata>\n"
"\tCONTROL:= reclassify | pipe | drop | continue | pass |\n"
"\t goto chain <CHAIN_INDEX>\n"
"\tNOTE: if 'ex' is set, extended functionality will be supported (kernel >= 4.11)\n"
"For Example usage look at the examples directory\n");
}
static void usage(void)
{
explain();
exit(-1);
}
static int pedit_parse_nopopt(int *argc_p, char ***argv_p,
struct m_pedit_sel *sel,
struct m_pedit_key *tkey)
{
int argc = *argc_p;
char **argv = *argv_p;
if (argc) {
fprintf(stderr,
"Unknown action hence option \"%s\" is unparsable\n",
*argv);
return -1;
}
return 0;
}
static struct m_pedit_util *get_pedit_kind(const char *str)
{
static void *pBODY;
void *dlh;
char buf[256];
struct m_pedit_util *p;
for (p = pedit_list; p; p = p->next) {
if (strcmp(p->id, str) == 0)
return p;
}
snprintf(buf, sizeof(buf), "p_%s.so", str);
dlh = dlopen(buf, RTLD_LAZY);
if (dlh == NULL) {
dlh = pBODY;
if (dlh == NULL) {
dlh = pBODY = dlopen(NULL, RTLD_LAZY);
if (dlh == NULL)
goto noexist;
}
}
snprintf(buf, sizeof(buf), "p_pedit_%s", str);
p = dlsym(dlh, buf);
if (p == NULL)
goto noexist;
reg:
p->next = pedit_list;
pedit_list = p;
return p;
noexist:
p = calloc(1, sizeof(*p));
if (p) {
strlcpy(p->id, str, sizeof(p->id));
p->parse_peopt = pedit_parse_nopopt;
goto reg;
}
return p;
}
static int pack_key(struct m_pedit_sel *_sel, struct m_pedit_key *tkey)
{
struct tc_pedit_sel *sel = &_sel->sel;
struct m_pedit_key_ex *keys_ex = _sel->keys_ex;
int hwm = sel->nkeys;
if (hwm >= MAX_OFFS)
return -1;
if (tkey->off % 4) {
fprintf(stderr, "offsets MUST be in 32 bit boundaries\n");
return -1;
}
sel->keys[hwm].val = tkey->val;
sel->keys[hwm].mask = tkey->mask;
sel->keys[hwm].off = tkey->off;
sel->keys[hwm].at = tkey->at;
sel->keys[hwm].offmask = tkey->offmask;
sel->keys[hwm].shift = tkey->shift;
if (_sel->extended) {
keys_ex[hwm].htype = tkey->htype;
keys_ex[hwm].cmd = tkey->cmd;
} else {
if (tkey->htype != TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK ||
tkey->cmd != TCA_PEDIT_KEY_EX_CMD_SET) {
fprintf(stderr,
"Munge parameters not supported. Use 'pedit ex munge ...'.\n");
return -1;
}
}
sel->nkeys++;
return 0;
}
static int pack_key32(__u32 retain, struct m_pedit_sel *sel,
struct m_pedit_key *tkey)
{
if (tkey->off > (tkey->off & ~3)) {
fprintf(stderr,
"pack_key32: 32 bit offsets must begin in 32bit boundaries\n");
return -1;
}
tkey->val = htonl(tkey->val & retain);
tkey->mask = htonl(tkey->mask | ~retain);
return pack_key(sel, tkey);
}
static int pack_key16(__u32 retain, struct m_pedit_sel *sel,
struct m_pedit_key *tkey)
{
int ind, stride;
__u32 m[4] = { 0x0000FFFF, 0xFF0000FF, 0xFFFF0000 };
if (tkey->val > 0xFFFF || tkey->mask > 0xFFFF) {
fprintf(stderr, "pack_key16 bad value\n");
return -1;
}
ind = tkey->off & 3;
if (ind == 3) {
fprintf(stderr, "pack_key16 bad index value %d\n", ind);
return -1;
}
stride = 8 * (2 - ind);
tkey->val = htonl((tkey->val & retain) << stride);
tkey->mask = htonl(((tkey->mask | ~retain) << stride) | m[ind]);
tkey->off &= ~3;
if (pedit_debug)
printf("pack_key16: Final val %08x mask %08x\n",
tkey->val, tkey->mask);
return pack_key(sel, tkey);
}
static int pack_key8(__u32 retain, struct m_pedit_sel *sel,
struct m_pedit_key *tkey)
{
int ind, stride;
__u32 m[4] = { 0x00FFFFFF, 0xFF00FFFF, 0xFFFF00FF, 0xFFFFFF00 };
if (tkey->val > 0xFF || tkey->mask > 0xFF) {
fprintf(stderr, "pack_key8 bad value (val %x mask %x\n",
tkey->val, tkey->mask);
return -1;
}
ind = tkey->off & 3;
stride = 8 * (3 - ind);
tkey->val = htonl((tkey->val & retain) << stride);
tkey->mask = htonl(((tkey->mask | ~retain) << stride) | m[ind]);
tkey->off &= ~3;
if (pedit_debug)
printf("pack_key8: Final word off %d val %08x mask %08x\n",
tkey->off, tkey->val, tkey->mask);
return pack_key(sel, tkey);
}
static int pack_mac(struct m_pedit_sel *sel, struct m_pedit_key *tkey,
__u8 *mac)
{
int ret = 0;
if (!(tkey->off & 0x3)) {
tkey->mask = 0;
tkey->val = ntohl(*((__u32 *)mac));
ret |= pack_key32(~0, sel, tkey);
tkey->off += 4;
tkey->mask = 0;
tkey->val = ntohs(*((__u16 *)&mac[4]));
ret |= pack_key16(~0, sel, tkey);
} else if (!(tkey->off & 0x1)) {
tkey->mask = 0;
tkey->val = ntohs(*((__u16 *)mac));
ret |= pack_key16(~0, sel, tkey);
tkey->off += 4;
tkey->mask = 0;
tkey->val = ntohl(*((__u32 *)(mac + 2)));
ret |= pack_key32(~0, sel, tkey);
} else {
fprintf(stderr,
"pack_mac: mac offsets must begin in 32bit or 16bit boundaries\n");
return -1;
}
return ret;
}
static int pack_ipv6(struct m_pedit_sel *sel, struct m_pedit_key *tkey,
__u32 *ipv6)
{
int ret = 0;
int i;
if (tkey->off & 0x3) {
fprintf(stderr,
"pack_ipv6: IPv6 offsets must begin in 32bit boundaries\n");
return -1;
}
for (i = 0; i < 4; i++) {
tkey->mask = 0;
tkey->val = ntohl(ipv6[i]);
ret = pack_key32(~0, sel, tkey);
if (ret)
return ret;
tkey->off += 4;
}
return 0;
}
static int parse_val(int *argc_p, char ***argv_p, __u32 *val, int type)
{
int argc = *argc_p;
char **argv = *argv_p;
if (argc <= 0)
return -1;
if (type == TINT)
return get_integer((int *)val, *argv, 0);
if (type == TU32)
return get_u32(val, *argv, 0);
if (type == TIPV4) {
inet_prefix addr;
if (get_prefix_1(&addr, *argv, AF_INET))
return -1;
*val = addr.data[0];
return 0;
}
if (type == TIPV6) {
inet_prefix addr;
if (get_prefix_1(&addr, *argv, AF_INET6))
return -1;
memcpy(val, addr.data, addr.bytelen);
return 0;
}
if (type == TMAC) {
#define MAC_ALEN 6
int ret = ll_addr_a2n((char *)val, MAC_ALEN, *argv);
if (ret == MAC_ALEN)
return 0;
}
return -1;
}
int parse_cmd(int *argc_p, char ***argv_p, __u32 len, int type, __u32 retain,
struct m_pedit_sel *sel, struct m_pedit_key *tkey)
{
__u32 mask[4] = { 0 };
__u32 val[4] = { 0 };
__u32 *m = &mask[0];
__u32 *v = &val[0];
__u32 o = 0xFF;
int res = -1;
int argc = *argc_p;
char **argv = *argv_p;
if (argc <= 0)
return -1;
if (pedit_debug)
printf("parse_cmd argc %d %s offset %d length %d\n",
argc, *argv, tkey->off, len);
if (len == 2)
o = 0xFFFF;
if (len == 4)
o = 0xFFFFFFFF;
if (matches(*argv, "invert") == 0) {
*v = *m = o;
} else if (matches(*argv, "set") == 0 ||
matches(*argv, "add") == 0) {
if (matches(*argv, "add") == 0)
tkey->cmd = TCA_PEDIT_KEY_EX_CMD_ADD;
if (!sel->extended && tkey->cmd) {
fprintf(stderr,
"Non extended mode. only 'set' command is supported\n");
return -1;
}
NEXT_ARG();
if (parse_val(&argc, &argv, val, type))
return -1;
} else if (matches(*argv, "preserve") == 0) {
retain = 0;
} else {
if (matches(*argv, "clear") != 0)
return -1;
}
argc--;
argv++;
if (argc && matches(*argv, "retain") == 0) {
NEXT_ARG();
if (parse_val(&argc, &argv, &retain, TU32))
return -1;
argc--;
argv++;
}
if (len > 4 && retain != ~0) {
fprintf(stderr,
"retain is not supported for fields longer the 32 bits\n");
return -1;
}
if (type == TMAC) {
res = pack_mac(sel, tkey, (__u8 *)val);
goto done;
}
if (type == TIPV6) {
res = pack_ipv6(sel, tkey, val);
goto done;
}
tkey->val = *v;
tkey->mask = *m;
if (type == TIPV4)
tkey->val = ntohl(tkey->val);
if (len == 1) {
res = pack_key8(retain, sel, tkey);
goto done;
}
if (len == 2) {
res = pack_key16(retain, sel, tkey);
goto done;
}
if (len == 4) {
res = pack_key32(retain, sel, tkey);
goto done;
}
return -1;
done:
if (pedit_debug)
printf("parse_cmd done argc %d %s offset %d length %d\n",
argc, *argv, tkey->off, len);
*argc_p = argc;
*argv_p = argv;
return res;
}
static int parse_offset(int *argc_p, char ***argv_p, struct m_pedit_sel *sel,
struct m_pedit_key *tkey)
{
int off;
__u32 len, retain;
int argc = *argc_p;
char **argv = *argv_p;
int res = -1;
if (argc <= 0)
return -1;
if (get_integer(&off, *argv, 0))
return -1;
tkey->off = off;
argc--;
argv++;
if (argc <= 0)
return -1;
if (matches(*argv, "u32") == 0) {
len = 4;
retain = 0xFFFFFFFF;
goto done;
}
if (matches(*argv, "u16") == 0) {
len = 2;
retain = 0xffff;
goto done;
}
if (matches(*argv, "u8") == 0) {
len = 1;
retain = 0xff;
goto done;
}
return -1;
done:
NEXT_ARG();
/* [at <someval> offmask <maskval> shift <shiftval>] */
if (matches(*argv, "at") == 0) {
__u32 atv = 0, offmask = 0x0, shift = 0;
NEXT_ARG();
if (get_u32(&atv, *argv, 0))
return -1;
tkey->at = atv;
NEXT_ARG();
if (get_u32(&offmask, *argv, 16))
return -1;
tkey->offmask = offmask;
NEXT_ARG();
if (get_u32(&shift, *argv, 0))
return -1;
tkey->shift = shift;
NEXT_ARG();
}
res = parse_cmd(&argc, &argv, len, TU32, retain, sel, tkey);
*argc_p = argc;
*argv_p = argv;
return res;
}
static int parse_munge(int *argc_p, char ***argv_p, struct m_pedit_sel *sel)
{
struct m_pedit_key tkey = {};
int argc = *argc_p;
char **argv = *argv_p;
int res = -1;
if (argc <= 0)
return -1;
if (matches(*argv, "offset") == 0) {
NEXT_ARG();
res = parse_offset(&argc, &argv, sel, &tkey);
goto done;
} else {
char k[FILTER_NAMESZ];
struct m_pedit_util *p = NULL;
strncpy(k, *argv, sizeof(k) - 1);
if (argc > 0) {
p = get_pedit_kind(k);
if (p == NULL)
goto bad_val;
NEXT_ARG();
res = p->parse_peopt(&argc, &argv, sel, &tkey);
if (res < 0) {
fprintf(stderr, "bad pedit parsing\n");
goto bad_val;
}
goto done;
}
}
bad_val:
return -1;
done:
*argc_p = argc;
*argv_p = argv;
return res;
}
static int pedit_keys_ex_getattr(struct rtattr *attr,
struct m_pedit_key_ex *keys_ex, int n)
{
struct rtattr *i;
int rem = RTA_PAYLOAD(attr);
struct rtattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
struct m_pedit_key_ex *k = keys_ex;
for (i = RTA_DATA(attr); RTA_OK(i, rem); i = RTA_NEXT(i, rem)) {
if (!n)
return -1;
if (i->rta_type != TCA_PEDIT_KEY_EX)
return -1;
parse_rtattr_nested(tb, TCA_PEDIT_KEY_EX_MAX, i);
k->htype = rta_getattr_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
k->cmd = rta_getattr_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
k++;
n--;
}
return !!n;
}
static int pedit_keys_ex_addattr(struct m_pedit_sel *sel, struct nlmsghdr *n)
{
struct m_pedit_key_ex *k = sel->keys_ex;
struct rtattr *keys_start;
int i;
if (!sel->extended)
return 0;
keys_start = addattr_nest(n, MAX_MSG, TCA_PEDIT_KEYS_EX | NLA_F_NESTED);
for (i = 0; i < sel->sel.nkeys; i++) {
struct rtattr *key_start;
key_start = addattr_nest(n, MAX_MSG,
TCA_PEDIT_KEY_EX | NLA_F_NESTED);
if (addattr16(n, MAX_MSG, TCA_PEDIT_KEY_EX_HTYPE, k->htype) ||
addattr16(n, MAX_MSG, TCA_PEDIT_KEY_EX_CMD, k->cmd)) {
return -1;
}
addattr_nest_end(n, key_start);
k++;
}
addattr_nest_end(n, keys_start);
return 0;
}
static int parse_pedit(struct action_util *a, int *argc_p, char ***argv_p,
int tca_id, struct nlmsghdr *n)
{
struct m_pedit_sel sel = {};
int argc = *argc_p;
char **argv = *argv_p;
int ok = 0, iok = 0;
struct rtattr *tail;
while (argc > 0) {
if (pedit_debug > 1)
fprintf(stderr, "while pedit (%d:%s)\n", argc, *argv);
if (matches(*argv, "pedit") == 0) {
NEXT_ARG();
ok++;
if (matches(*argv, "ex") == 0) {
if (ok > 1) {
fprintf(stderr,
"'ex' must be before first 'munge'\n");
explain();
return -1;
}
sel.extended = true;
NEXT_ARG();
}
continue;
} else if (matches(*argv, "help") == 0) {
usage();
} else if (matches(*argv, "munge") == 0) {
if (!ok) {
fprintf(stderr, "Bad pedit construct (%s)\n",
*argv);
explain();
return -1;
}
NEXT_ARG();
if (parse_munge(&argc, &argv, &sel)) {
fprintf(stderr, "Bad pedit construct (%s)\n",
*argv);
explain();
return -1;
}
ok++;
} else {
break;
}
}
if (!ok) {
explain();
return -1;
}
parse_action_control_dflt(&argc, &argv, &sel.sel.action, false, TC_ACT_OK);
if (argc) {
if (matches(*argv, "index") == 0) {
NEXT_ARG();
if (get_u32(&sel.sel.index, *argv, 10)) {
fprintf(stderr, "Pedit: Illegal \"index\"\n");
return -1;
}
argc--;
argv++;
iok++;
}
}
tail = addattr_nest(n, MAX_MSG, tca_id);
if (!sel.extended) {
addattr_l(n, MAX_MSG, TCA_PEDIT_PARMS, &sel,
sizeof(sel.sel) +
sel.sel.nkeys * sizeof(struct tc_pedit_key));
} else {
addattr_l(n, MAX_MSG, TCA_PEDIT_PARMS_EX, &sel,
sizeof(sel.sel) +
sel.sel.nkeys * sizeof(struct tc_pedit_key));
pedit_keys_ex_addattr(&sel, n);
}
addattr_nest_end(n, tail);
*argc_p = argc;
*argv_p = argv;
return 0;
}
static const char * const pedit_htype_str[] = {
[TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK] = "",
[TCA_PEDIT_KEY_EX_HDR_TYPE_ETH] = "eth",
[TCA_PEDIT_KEY_EX_HDR_TYPE_IP4] = "ipv4",
[TCA_PEDIT_KEY_EX_HDR_TYPE_IP6] = "ipv6",
[TCA_PEDIT_KEY_EX_HDR_TYPE_TCP] = "tcp",
[TCA_PEDIT_KEY_EX_HDR_TYPE_UDP] = "udp",
};
static int print_pedit_location(FILE *f,
enum pedit_header_type htype, __u32 off)
{
char *buf = NULL;
int rc;
if (htype != TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK) {
if (htype < ARRAY_SIZE(pedit_htype_str))
rc = asprintf(&buf, "%s", pedit_htype_str[htype]);
else
rc = asprintf(&buf, "unknown(%d)", htype);
if (rc < 0)
return rc;
print_string(PRINT_ANY, "htype", "%s", buf);
print_int(PRINT_ANY, "offset", "%+d", off);
} else {
print_string(PRINT_JSON, "htype", NULL, "network");
print_int(PRINT_ANY, "offset", "%d", off);
}
free(buf);
return 0;
}
static int print_pedit(struct action_util *au, FILE *f, struct rtattr *arg)
{
struct tc_pedit_sel *sel;
struct rtattr *tb[TCA_PEDIT_MAX + 1];
struct m_pedit_key_ex *keys_ex = NULL;
int err;
if (arg == NULL)
return -1;
parse_rtattr_nested(tb, TCA_PEDIT_MAX, arg);
if (!tb[TCA_PEDIT_PARMS] && !tb[TCA_PEDIT_PARMS_EX]) {
fprintf(stderr, "Missing pedit parameters\n");
return -1;
}
if (tb[TCA_PEDIT_PARMS]) {
sel = RTA_DATA(tb[TCA_PEDIT_PARMS]);
} else {
int err;
sel = RTA_DATA(tb[TCA_PEDIT_PARMS_EX]);
if (!tb[TCA_PEDIT_KEYS_EX]) {
fprintf(f, "Netlink error\n");
return -1;
}
keys_ex = calloc(sel->nkeys, sizeof(*keys_ex));
if (!keys_ex) {
fprintf(f, "Out of memory\n");
return -1;
}
err = pedit_keys_ex_getattr(tb[TCA_PEDIT_KEYS_EX], keys_ex,
sel->nkeys);
if (err) {
fprintf(f, "Netlink error\n");
free(keys_ex);
return -1;
}
}
print_string(PRINT_ANY, "kind", " %s ", "pedit");
print_action_control(f, "action ", sel->action, " ");
print_uint(PRINT_ANY, "nkeys", "keys %d\n", sel->nkeys);
print_uint(PRINT_ANY, "index", " \t index %u", sel->index);
print_int(PRINT_ANY, "ref", " ref %d", sel->refcnt);
print_int(PRINT_ANY, "bind", " bind %d", sel->bindcnt);
if (show_stats) {
if (tb[TCA_PEDIT_TM]) {
struct tcf_t *tm = RTA_DATA(tb[TCA_PEDIT_TM]);
print_tm(f, tm);
}
}
open_json_array(PRINT_JSON, "keys");
if (sel->nkeys) {
int i;
struct tc_pedit_key *key = sel->keys;
struct m_pedit_key_ex *key_ex = keys_ex;
for (i = 0; i < sel->nkeys; i++, key++) {
enum pedit_header_type htype =
TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
if (keys_ex) {
htype = key_ex->htype;
cmd = key_ex->cmd;
key_ex++;
}
open_json_object(NULL);
print_uint(PRINT_FP, NULL, "\n\t key #%d at ", i);
err = print_pedit_location(f, htype, key->off);
if (err)
return err;
/* In FP, report the "set" command as "val" to keep
* backward compatibility. Report the true name in JSON.
*/
print_string(PRINT_FP, NULL, ": %s",
cmd ? "add" : "val");
print_string(PRINT_JSON, "cmd", NULL,
cmd ? "add" : "set");
print_hex(PRINT_ANY, "val", " %08x",
(unsigned int)ntohl(key->val));
print_hex(PRINT_ANY, "mask", " mask %08x",
(unsigned int)ntohl(key->mask));
close_json_object();
}
} else {
fprintf(f, "\npedit %x keys %d is not LEGIT", sel->index,
sel->nkeys);
}
close_json_array(PRINT_JSON, " ");
print_nl();
free(keys_ex);
return 0;
}
struct action_util pedit_action_util = {
.id = "pedit",
.parse_aopt = parse_pedit,
.print_aopt = print_pedit,
};