| /* Kernel module to match ROUTING 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_ipv6/ip6_tables.h> |
| #include <linux/netfilter_ipv6/ip6t_rt.h> |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_DESCRIPTION("IPv6 RT match"); |
| MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>"); |
| |
| #if 0 |
| #define DEBUGP printk |
| #else |
| #define DEBUGP(format, args...) |
| #endif |
| |
| /* Returns 1 if the id is matched by the range, 0 otherwise */ |
| static inline int |
| segsleft_match(u_int32_t min, u_int32_t max, u_int32_t id, int invert) |
| { |
| int r=0; |
| DEBUGP("rt segsleft_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ', |
| min,id,max); |
| r=(id >= min && id <= max) ^ invert; |
| DEBUGP(" result %s\n",r? "PASS" : "FAILED"); |
| return r; |
| } |
| |
| static int |
| match(const struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| const void *matchinfo, |
| int offset, |
| unsigned int protoff, |
| int *hotdrop) |
| { |
| struct ipv6_rt_hdr _route, *rh = NULL; |
| const struct ip6t_rt *rtinfo = matchinfo; |
| unsigned int temp; |
| unsigned int len; |
| u8 nexthdr; |
| unsigned int ptr; |
| unsigned int hdrlen = 0; |
| unsigned int ret = 0; |
| struct in6_addr *ap, _addr; |
| |
| /* type of the 1st exthdr */ |
| nexthdr = skb->nh.ipv6h->nexthdr; |
| /* pointer to the 1st exthdr */ |
| ptr = sizeof(struct ipv6hdr); |
| /* available length */ |
| len = skb->len - ptr; |
| temp = 0; |
| |
| while (ip6t_ext_hdr(nexthdr)) { |
| struct ipv6_opt_hdr _hdr, *hp; |
| |
| DEBUGP("ipv6_rt header iteration \n"); |
| |
| /* Is there enough space for the next ext header? */ |
| if (len < (int)sizeof(struct ipv6_opt_hdr)) |
| return 0; |
| /* No more exthdr -> evaluate */ |
| if (nexthdr == NEXTHDR_NONE) { |
| break; |
| } |
| /* ESP -> evaluate */ |
| if (nexthdr == NEXTHDR_ESP) { |
| break; |
| } |
| |
| hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr); |
| BUG_ON(hp == NULL); |
| |
| /* Calculate the header length */ |
| if (nexthdr == NEXTHDR_FRAGMENT) { |
| hdrlen = 8; |
| } else if (nexthdr == NEXTHDR_AUTH) |
| hdrlen = (hp->hdrlen+2)<<2; |
| else |
| hdrlen = ipv6_optlen(hp); |
| |
| /* ROUTING -> evaluate */ |
| if (nexthdr == NEXTHDR_ROUTING) { |
| temp |= MASK_ROUTING; |
| break; |
| } |
| |
| |
| /* set the flag */ |
| switch (nexthdr){ |
| case NEXTHDR_HOP: |
| case NEXTHDR_ROUTING: |
| case NEXTHDR_FRAGMENT: |
| case NEXTHDR_AUTH: |
| case NEXTHDR_DEST: |
| break; |
| default: |
| DEBUGP("ipv6_rt match: unknown nextheader %u\n",nexthdr); |
| return 0; |
| break; |
| } |
| |
| nexthdr = hp->nexthdr; |
| len -= hdrlen; |
| ptr += hdrlen; |
| if ( ptr > skb->len ) { |
| DEBUGP("ipv6_rt: new pointer is too large! \n"); |
| break; |
| } |
| } |
| |
| /* ROUTING header not found */ |
| if ( temp != MASK_ROUTING ) return 0; |
| |
| if (len < (int)sizeof(struct ipv6_rt_hdr)){ |
| *hotdrop = 1; |
| return 0; |
| } |
| |
| if (len < hdrlen){ |
| /* Pcket smaller than its length field */ |
| return 0; |
| } |
| |
| rh = skb_header_pointer(skb, ptr, sizeof(_route), &_route); |
| BUG_ON(rh == NULL); |
| |
| DEBUGP("IPv6 RT LEN %u %u ", hdrlen, rh->hdrlen); |
| DEBUGP("TYPE %04X ", rh->type); |
| DEBUGP("SGS_LEFT %u %02X\n", rh->segments_left, rh->segments_left); |
| |
| DEBUGP("IPv6 RT segsleft %02X ", |
| (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1], |
| rh->segments_left, |
| !!(rtinfo->invflags & IP6T_RT_INV_SGS)))); |
| DEBUGP("type %02X %02X %02X ", |
| rtinfo->rt_type, rh->type, |
| (!(rtinfo->flags & IP6T_RT_TYP) || |
| ((rtinfo->rt_type == rh->type) ^ |
| !!(rtinfo->invflags & IP6T_RT_INV_TYP)))); |
| DEBUGP("len %02X %04X %02X ", |
| rtinfo->hdrlen, hdrlen, |
| (!(rtinfo->flags & IP6T_RT_LEN) || |
| ((rtinfo->hdrlen == hdrlen) ^ |
| !!(rtinfo->invflags & IP6T_RT_INV_LEN)))); |
| DEBUGP("res %02X %02X %02X ", |
| (rtinfo->flags & IP6T_RT_RES), ((struct rt0_hdr *)rh)->bitmap, |
| !((rtinfo->flags & IP6T_RT_RES) && (((struct rt0_hdr *)rh)->bitmap))); |
| |
| ret = (rh != NULL) |
| && |
| (segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1], |
| rh->segments_left, |
| !!(rtinfo->invflags & IP6T_RT_INV_SGS))) |
| && |
| (!(rtinfo->flags & IP6T_RT_LEN) || |
| ((rtinfo->hdrlen == hdrlen) ^ |
| !!(rtinfo->invflags & IP6T_RT_INV_LEN))) |
| && |
| (!(rtinfo->flags & IP6T_RT_TYP) || |
| ((rtinfo->rt_type == rh->type) ^ |
| !!(rtinfo->invflags & IP6T_RT_INV_TYP))); |
| |
| if (ret && (rtinfo->flags & IP6T_RT_RES)) { |
| u_int32_t *bp, _bitmap; |
| bp = skb_header_pointer(skb, |
| ptr + offsetof(struct rt0_hdr, bitmap), |
| sizeof(_bitmap), &_bitmap); |
| |
| ret = (*bp == 0); |
| } |
| |
| DEBUGP("#%d ",rtinfo->addrnr); |
| if ( !(rtinfo->flags & IP6T_RT_FST) ){ |
| return ret; |
| } else if (rtinfo->flags & IP6T_RT_FST_NSTRICT) { |
| DEBUGP("Not strict "); |
| if ( rtinfo->addrnr > (unsigned int)((hdrlen-8)/16) ){ |
| DEBUGP("There isn't enough space\n"); |
| return 0; |
| } else { |
| unsigned int i = 0; |
| |
| DEBUGP("#%d ",rtinfo->addrnr); |
| for(temp=0; temp<(unsigned int)((hdrlen-8)/16); temp++){ |
| ap = skb_header_pointer(skb, |
| ptr |
| + sizeof(struct rt0_hdr) |
| + temp * sizeof(_addr), |
| sizeof(_addr), |
| &_addr); |
| |
| BUG_ON(ap == NULL); |
| |
| if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) { |
| DEBUGP("i=%d temp=%d;\n",i,temp); |
| i++; |
| } |
| if (i==rtinfo->addrnr) break; |
| } |
| DEBUGP("i=%d #%d\n", i, rtinfo->addrnr); |
| if (i == rtinfo->addrnr) |
| return ret; |
| else return 0; |
| } |
| } else { |
| DEBUGP("Strict "); |
| if ( rtinfo->addrnr > (unsigned int)((hdrlen-8)/16) ){ |
| DEBUGP("There isn't enough space\n"); |
| return 0; |
| } else { |
| DEBUGP("#%d ",rtinfo->addrnr); |
| for(temp=0; temp<rtinfo->addrnr; temp++){ |
| ap = skb_header_pointer(skb, |
| ptr |
| + sizeof(struct rt0_hdr) |
| + temp * sizeof(_addr), |
| sizeof(_addr), |
| &_addr); |
| BUG_ON(ap == NULL); |
| |
| if (!ipv6_addr_equal(ap, &rtinfo->addrs[temp])) |
| break; |
| } |
| DEBUGP("temp=%d #%d\n", temp, rtinfo->addrnr); |
| if ((temp == rtinfo->addrnr) && (temp == (unsigned int)((hdrlen-8)/16))) |
| return ret; |
| else return 0; |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* Called when user tries to insert an entry of this type. */ |
| static int |
| checkentry(const char *tablename, |
| const struct ip6t_ip6 *ip, |
| void *matchinfo, |
| unsigned int matchinfosize, |
| unsigned int hook_mask) |
| { |
| const struct ip6t_rt *rtinfo = matchinfo; |
| |
| if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_rt))) { |
| DEBUGP("ip6t_rt: matchsize %u != %u\n", |
| matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_rt))); |
| return 0; |
| } |
| if (rtinfo->invflags & ~IP6T_RT_INV_MASK) { |
| DEBUGP("ip6t_rt: unknown flags %X\n", |
| rtinfo->invflags); |
| return 0; |
| } |
| if ( (rtinfo->flags & (IP6T_RT_RES|IP6T_RT_FST_MASK)) && |
| (!(rtinfo->flags & IP6T_RT_TYP) || |
| (rtinfo->rt_type != 0) || |
| (rtinfo->invflags & IP6T_RT_INV_TYP)) ) { |
| DEBUGP("`--rt-type 0' required before `--rt-0-*'"); |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| static struct ip6t_match rt_match = { |
| .name = "rt", |
| .match = &match, |
| .checkentry = &checkentry, |
| .me = THIS_MODULE, |
| }; |
| |
| static int __init init(void) |
| { |
| return ip6t_register_match(&rt_match); |
| } |
| |
| static void __exit cleanup(void) |
| { |
| ip6t_unregister_match(&rt_match); |
| } |
| |
| module_init(init); |
| module_exit(cleanup); |
