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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /net/netfilter/xt_CHECKSUM.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | net/netfilter/xt_CHECKSUM.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/net/netfilter/xt_CHECKSUM.c b/net/netfilter/xt_CHECKSUM.c new file mode 100644 index 000000000..c8a639f56 --- /dev/null +++ b/net/netfilter/xt_CHECKSUM.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* iptables module for the packet checksum mangling + * + * (C) 2002 by Harald Welte <laforge@netfilter.org> + * (C) 2010 Red Hat, Inc. + * + * Author: Michael S. Tsirkin <mst@redhat.com> +*/ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/module.h> +#include <linux/skbuff.h> + +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter/xt_CHECKSUM.h> + +#include <linux/netfilter_ipv4/ip_tables.h> +#include <linux/netfilter_ipv6/ip6_tables.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Michael S. Tsirkin <mst@redhat.com>"); +MODULE_DESCRIPTION("Xtables: checksum modification"); +MODULE_ALIAS("ipt_CHECKSUM"); +MODULE_ALIAS("ip6t_CHECKSUM"); + +static unsigned int +checksum_tg(struct sk_buff *skb, const struct xt_action_param *par) +{ + if (skb->ip_summed == CHECKSUM_PARTIAL && !skb_is_gso(skb)) + skb_checksum_help(skb); + + return XT_CONTINUE; +} + +static int checksum_tg_check(const struct xt_tgchk_param *par) +{ + const struct xt_CHECKSUM_info *einfo = par->targinfo; + const struct ip6t_ip6 *i6 = par->entryinfo; + const struct ipt_ip *i4 = par->entryinfo; + + if (einfo->operation & ~XT_CHECKSUM_OP_FILL) { + pr_info_ratelimited("unsupported CHECKSUM operation %x\n", + einfo->operation); + return -EINVAL; + } + if (!einfo->operation) + return -EINVAL; + + switch (par->family) { + case NFPROTO_IPV4: + if (i4->proto == IPPROTO_UDP && + (i4->invflags & XT_INV_PROTO) == 0) + return 0; + break; + case NFPROTO_IPV6: + if ((i6->flags & IP6T_F_PROTO) && + i6->proto == IPPROTO_UDP && + (i6->invflags & XT_INV_PROTO) == 0) + return 0; + break; + } + + pr_warn_once("CHECKSUM should be avoided. If really needed, restrict with \"-p udp\" and only use in OUTPUT\n"); + return 0; +} + +static struct xt_target checksum_tg_reg __read_mostly = { + .name = "CHECKSUM", + .family = NFPROTO_UNSPEC, + .target = checksum_tg, + .targetsize = sizeof(struct xt_CHECKSUM_info), + .table = "mangle", + .checkentry = checksum_tg_check, + .me = THIS_MODULE, +}; + +static int __init checksum_tg_init(void) +{ + return xt_register_target(&checksum_tg_reg); +} + +static void __exit checksum_tg_exit(void) +{ + xt_unregister_target(&checksum_tg_reg); +} + +module_init(checksum_tg_init); +module_exit(checksum_tg_exit); |