diff options
Diffstat (limited to 'net/netfilter/xt_physdev.c')
| -rw-r--r-- | net/netfilter/xt_physdev.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/net/netfilter/xt_physdev.c b/net/netfilter/xt_physdev.c new file mode 100644 index 000000000..343e65f37 --- /dev/null +++ b/net/netfilter/xt_physdev.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Kernel module to match the bridge port in and + * out device for IP packets coming into contact with a bridge. */ + +/* (C) 2001-2003 Bart De Schuymer <bdschuym@pandora.be> + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/if.h> +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/netfilter_bridge.h> +#include <linux/netfilter/x_tables.h> +#include <uapi/linux/netfilter/xt_physdev.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>"); +MODULE_DESCRIPTION("Xtables: Bridge physical device match"); +MODULE_ALIAS("ipt_physdev"); +MODULE_ALIAS("ip6t_physdev"); + + +static bool +physdev_mt(const struct sk_buff *skb, struct xt_action_param *par) +{ + const struct xt_physdev_info *info = par->matchinfo; + const struct net_device *physdev; + unsigned long ret; + const char *indev, *outdev; + + /* Not a bridged IP packet or no info available yet: + * LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if + * the destination device will be a bridge. */ + if (!nf_bridge_info_exists(skb)) { + /* Return MATCH if the invert flags of the used options are on */ + if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) && + !(info->invert & XT_PHYSDEV_OP_BRIDGED)) + return false; + if ((info->bitmask & XT_PHYSDEV_OP_ISIN) && + !(info->invert & XT_PHYSDEV_OP_ISIN)) + return false; + if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) && + !(info->invert & XT_PHYSDEV_OP_ISOUT)) + return false; + if ((info->bitmask & XT_PHYSDEV_OP_IN) && + !(info->invert & XT_PHYSDEV_OP_IN)) + return false; + if ((info->bitmask & XT_PHYSDEV_OP_OUT) && + !(info->invert & XT_PHYSDEV_OP_OUT)) + return false; + return true; + } + + physdev = nf_bridge_get_physoutdev(skb); + outdev = physdev ? physdev->name : NULL; + + /* This only makes sense in the FORWARD and POSTROUTING chains */ + if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) && + (!!outdev ^ !(info->invert & XT_PHYSDEV_OP_BRIDGED))) + return false; + + physdev = nf_bridge_get_physindev(skb, xt_net(par)); + indev = physdev ? physdev->name : NULL; + + if ((info->bitmask & XT_PHYSDEV_OP_ISIN && + (!indev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) || + (info->bitmask & XT_PHYSDEV_OP_ISOUT && + (!outdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT)))) + return false; + + if (!(info->bitmask & XT_PHYSDEV_OP_IN)) + goto match_outdev; + + if (indev) { + ret = ifname_compare_aligned(indev, info->physindev, + info->in_mask); + + if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN)) + return false; + } + +match_outdev: + if (!(info->bitmask & XT_PHYSDEV_OP_OUT)) + return true; + + if (!outdev) + return false; + + ret = ifname_compare_aligned(outdev, info->physoutdev, info->out_mask); + + return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT)); +} + +static int physdev_mt_check(const struct xt_mtchk_param *par) +{ + const struct xt_physdev_info *info = par->matchinfo; + static bool brnf_probed __read_mostly; + + if (!(info->bitmask & XT_PHYSDEV_OP_MASK) || + info->bitmask & ~XT_PHYSDEV_OP_MASK) + return -EINVAL; + if (info->bitmask & (XT_PHYSDEV_OP_OUT | XT_PHYSDEV_OP_ISOUT) && + (!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) || + info->invert & XT_PHYSDEV_OP_BRIDGED) && + par->hook_mask & (1 << NF_INET_LOCAL_OUT)) { + pr_info_ratelimited("--physdev-out and --physdev-is-out only supported in the FORWARD and POSTROUTING chains with bridged traffic\n"); + return -EINVAL; + } + + if (!brnf_probed) { + brnf_probed = true; + request_module("br_netfilter"); + } + + return 0; +} + +static struct xt_match physdev_mt_reg __read_mostly = { + .name = "physdev", + .revision = 0, + .family = NFPROTO_UNSPEC, + .checkentry = physdev_mt_check, + .match = physdev_mt, + .matchsize = sizeof(struct xt_physdev_info), + .me = THIS_MODULE, +}; + +static int __init physdev_mt_init(void) +{ + return xt_register_match(&physdev_mt_reg); +} + +static void __exit physdev_mt_exit(void) +{ + xt_unregister_match(&physdev_mt_reg); +} + +module_init(physdev_mt_init); +module_exit(physdev_mt_exit); |