extensions: libipt_icmp: Add translation to nft
PATCH v5 1/1 extensions: libipt_icmp: Add translation to nft
Add translation for icmp to nftables. Not supported types in nftables
are: any, network-unreachable, host-unreachable, protocol-unreachable, port-unreachable, fragmentation-needed, source-route-failed,
network-unknown, host-unknown, network-prohibited, host-prohibited, TOS-network-unreachable, TOS-host-unreachable, communication-prohibited, host-precedence-violation, precedence-cutoff, network-redirect,
host-redirect, TOS-network-redirect, TOS-host-redirect,
ttl-zero-during-transit, ttl-zero-during-reassembly, ip-header-bad and required-option-missing.
Examples:
$ sudo iptables-translate -t filter -A INPUT -m icmp --icmp-type echo-reply -j ACCEPT nft add rule ip filter INPUT icmp type echo-reply counter accept
$ sudo iptables-translate -t filter -A INPUT -m icmp --icmp-type 3 -j ACCEPT nft add rule ip filter INPUT icmp type destination-unreachable counter accept
$ sudo iptables-translate -t filter -A INPUT -m icmp ! --icmp-type 3 -j ACCEPT nft add rule ip filter INPUT icmp type != destination-unreachable counter accept
---
v2:
- Detection of not supported types in nftables, as Shivani suggested.
v3:
- Fix array iteration protection.
v4:
- icmp types router-advertisement and router-solicitation already supported in nft.
v5:
- Update commit message with the correct not supported codes.
extensions/libipt_icmp.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+)
extensions/libipt_icmp.c +36 -0
@@ -249,6 +249,41 @@ static void icmp_save(const void *ip, const struct xt_entry_match *match) } } +static unsigned int type_xlate_print (struct xt_xlate *xl,unsigned int icmptype, +unsigned int code_min, +unsigned int code_max) +{ +unsigned int i; + +if (code_min != code_max && icmptype !=0xFF ) { +for (i =0 ; i <ARRAY_SIZE (icmp_codes); ++i) +if (icmp_codes[i].type == icmptype && + icmp_codes[i].code_min == code_min && + icmp_codes[i].code_max == code_max) { +xt_xlate_add (xl, icmp_codes[i].name); +return 1 ; + } + } + +return 0 ; +} + +static int icmp_xlate (const struct xt_entry_match *match,struct xt_xlate *xl, +int numeric) +{ +const struct ipt_icmp *info = (struct ipt_icmp *)match->data; + +xt_xlate_add (xl,"icmp type%s " , + (info->invflags &IPT_ICMP_INV ) ?" !=" :"" ); + +if (!type_xlate_print (xl, info->type, info->code[0 ], info->code[1 ])) +return 0 ; + +xt_xlate_add (xl," " ); + +return 1 ; +} +static struct xtables_match icmp_mt_reg = { .name ="icmp" , .version =XTABLES_VERSION ,
@@ -261,6 +296,7 @@ static struct xtables_match icmp_mt_reg = { .save = icmp_save, .x6_parse = icmp_parse, .x6_options = icmp_opts, + .xlate = icmp_xlate, };void _init (void )
Signature · 1 line
2.7.0
Pablo Neira Ayuso
maintainerQuoted 1 line · Laura Garcia Liebana
Add translation for icmp to nftables. Not supported types in nftables
Please, this should be "Not supported icmp codes in nftables" instead.
Quoted 1 line
are: any, network-unreachable, host-unreachable, protocol-unreachable,
'any' is equivalent to void translation.
Quoted 1 line
From what I can see in iptables, this built-in match comes with this
wildcard 'any' icmp type just to check that the icmp header is actually in place.
In nft, we can rely on the connection tracking for such a check.
Quoted 37 lines
port-unreachable, fragmentation-needed, source-route-failed,
network-unknown, host-unknown, network-prohibited, host-prohibited, TOS-network-unreachable, TOS-host-unreachable, communication-prohibited, host-precedence-violation, precedence-cutoff, network-redirect,
host-redirect, TOS-network-redirect, TOS-host-redirect,
ttl-zero-during-transit, ttl-zero-during-reassembly, ip-header-bad and required-option-missing.Examples:
$ sudo iptables-translate -t filter -A INPUT -m icmp --icmp-type echo-reply -j ACCEPT nft add rule ip filter INPUT icmp type echo-reply counter accept$ sudo iptables-translate -t filter -A INPUT -m icmp --icmp-type 3 -j ACCEPT nft add rule ip filter INPUT icmp type destination-unreachable counter accept$ sudo iptables-translate -t filter -A INPUT -m icmp ! --icmp-type 3 -j ACCEPT nft add rule ip filter INPUT icmp type != destination-unreachable counter acceptSigned-off-by Laura Garcia Liebana <[email protected]>---
v2:
- Detection of not supported types in nftables, as Shivani suggested.
v3:
- Fix array iteration protection.
v4:
- icmp types router-advertisement and router-solicitation already supported in nft.
v5:
- Update commit message with the correct not supported codes.extensions/libipt_icmp.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+)extensions/libipt_icmp.c +0
-0
extensions/libipt_icmp.c static void icmp_save(const void *ip, const struct xt_entry_match *match) · line 258
Quoted 10 lines
extensions/libipt_icmp.c +7
-0@@ -249,6 +249,41 @@ static void icmp_save(const void *ip, const struct xt_entry_match *match) } } +static unsigned int type_xlate_print (struct xt_xlate *xl,unsigned int icmptype, +unsigned int code_min, +unsigned int code_max) +{ +unsigned int i; + +if (code_min != code_max && icmptype !=0xFF ) {
So, if icmptype == 0xff, just return 1 with no printing I'd suggest.
Quoted 11 lines
extensions/libipt_icmp.c +11
-0+for (i =0 ; i <ARRAY_SIZE (icmp_codes); ++i) +if (icmp_codes[i].type == icmptype && + icmp_codes[i].code_min == code_min && + icmp_codes[i].code_max == code_max) { +xt_xlate_add (xl, icmp_codes[i].name); +return 1 ; + } + } + +return 0 ; +}