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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [net/] [ipv6/] [netfilter/] [ip6t_hbh.c] - Rev 3
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/* Kernel module to match Hop-by-Hop and Destination parameters. */ /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/module.h> #include <linux/skbuff.h> #include <linux/ipv6.h> #include <linux/types.h> #include <net/checksum.h> #include <net/ipv6.h> #include <asm/byteorder.h> #include <linux/netfilter/x_tables.h> #include <linux/netfilter_ipv6/ip6_tables.h> #include <linux/netfilter_ipv6/ip6t_opts.h> MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("IPv6 opts match"); MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>"); MODULE_ALIAS("ip6t_dst"); /* * (Type & 0xC0) >> 6 * 0 -> ignorable * 1 -> must drop the packet * 2 -> send ICMP PARM PROB regardless and drop packet * 3 -> Send ICMP if not a multicast address and drop packet * (Type & 0x20) >> 5 * 0 -> invariant * 1 -> can change the routing * (Type & 0x1F) Type * 0 -> Pad1 (only 1 byte!) * 1 -> PadN LENGTH info (total length = length + 2) * C0 | 2 -> JUMBO 4 x x x x ( xxxx > 64k ) * 5 -> RTALERT 2 x x */ static bool match(const struct sk_buff *skb, const struct net_device *in, const struct net_device *out, const struct xt_match *match, const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop) { struct ipv6_opt_hdr _optsh; const struct ipv6_opt_hdr *oh; const struct ip6t_opts *optinfo = matchinfo; unsigned int temp; unsigned int ptr; unsigned int hdrlen = 0; bool ret = false; u8 _opttype; u8 _optlen; const u_int8_t *tp = NULL; const u_int8_t *lp = NULL; unsigned int optlen; int err; err = ipv6_find_hdr(skb, &ptr, match->data, NULL); if (err < 0) { if (err != -ENOENT) *hotdrop = true; return false; } oh = skb_header_pointer(skb, ptr, sizeof(_optsh), &_optsh); if (oh == NULL) { *hotdrop = true; return false; } hdrlen = ipv6_optlen(oh); if (skb->len - ptr < hdrlen) { /* Packet smaller than it's length field */ return false; } pr_debug("IPv6 OPTS LEN %u %u ", hdrlen, oh->hdrlen); pr_debug("len %02X %04X %02X ", optinfo->hdrlen, hdrlen, (!(optinfo->flags & IP6T_OPTS_LEN) || ((optinfo->hdrlen == hdrlen) ^ !!(optinfo->invflags & IP6T_OPTS_INV_LEN)))); ret = (oh != NULL) && (!(optinfo->flags & IP6T_OPTS_LEN) || ((optinfo->hdrlen == hdrlen) ^ !!(optinfo->invflags & IP6T_OPTS_INV_LEN))); ptr += 2; hdrlen -= 2; if (!(optinfo->flags & IP6T_OPTS_OPTS)) { return ret; } else if (optinfo->flags & IP6T_OPTS_NSTRICT) { pr_debug("Not strict - not implemented"); } else { pr_debug("Strict "); pr_debug("#%d ", optinfo->optsnr); for (temp = 0; temp < optinfo->optsnr; temp++) { /* type field exists ? */ if (hdrlen < 1) break; tp = skb_header_pointer(skb, ptr, sizeof(_opttype), &_opttype); if (tp == NULL) break; /* Type check */ if (*tp != (optinfo->opts[temp] & 0xFF00) >> 8) { pr_debug("Tbad %02X %02X\n", *tp, (optinfo->opts[temp] & 0xFF00) >> 8); return false; } else { pr_debug("Tok "); } /* Length check */ if (*tp) { u16 spec_len; /* length field exists ? */ if (hdrlen < 2) break; lp = skb_header_pointer(skb, ptr + 1, sizeof(_optlen), &_optlen); if (lp == NULL) break; spec_len = optinfo->opts[temp] & 0x00FF; if (spec_len != 0x00FF && spec_len != *lp) { pr_debug("Lbad %02X %04X\n", *lp, spec_len); return false; } pr_debug("Lok "); optlen = *lp + 2; } else { pr_debug("Pad1\n"); optlen = 1; } /* Step to the next */ pr_debug("len%04X \n", optlen); if ((ptr > skb->len - optlen || hdrlen < optlen) && temp < optinfo->optsnr - 1) { pr_debug("new pointer is too large! \n"); break; } ptr += optlen; hdrlen -= optlen; } if (temp == optinfo->optsnr) return ret; else return false; } return false; } /* Called when user tries to insert an entry of this type. */ static bool checkentry(const char *tablename, const void *entry, const struct xt_match *match, void *matchinfo, unsigned int hook_mask) { const struct ip6t_opts *optsinfo = matchinfo; if (optsinfo->invflags & ~IP6T_OPTS_INV_MASK) { pr_debug("ip6t_opts: unknown flags %X\n", optsinfo->invflags); return false; } return true; } static struct xt_match opts_match[] __read_mostly = { { .name = "hbh", .family = AF_INET6, .match = match, .matchsize = sizeof(struct ip6t_opts), .checkentry = checkentry, .me = THIS_MODULE, .data = NEXTHDR_HOP, }, { .name = "dst", .family = AF_INET6, .match = match, .matchsize = sizeof(struct ip6t_opts), .checkentry = checkentry, .me = THIS_MODULE, .data = NEXTHDR_DEST, }, }; static int __init ip6t_hbh_init(void) { return xt_register_matches(opts_match, ARRAY_SIZE(opts_match)); } static void __exit ip6t_hbh_fini(void) { xt_unregister_matches(opts_match, ARRAY_SIZE(opts_match)); } module_init(ip6t_hbh_init); module_exit(ip6t_hbh_fini);