/* 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 intsegsleft_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 intmatch(const struct sk_buff *skb,      const struct net_device *in,      const struct net_device *out,      const void *matchinfo,      int offset,      const void *protohdr,      u_int16_t datalen,      int *hotdrop){       struct ipv6_rt_hdr *route = 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;       /* 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;              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;              }              hdr=(struct ipv6_opt_hdr *)skb->data+ptr;              /* Calculate the header length */                if (nexthdr == NEXTHDR_FRAGMENT) {                        hdrlen = 8;                } else if (nexthdr == NEXTHDR_AUTH)                        hdrlen = (hdr->hdrlen+2)<<2;                else                        hdrlen = ipv6_optlen(hdr);              /* 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 = hdr->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;       }       route = (struct ipv6_rt_hdr *) (skb->data + ptr);       DEBUGP("IPv6 RT LEN %u %u ", hdrlen, route->hdrlen);       DEBUGP("TYPE %04X ", route->type);       DEBUGP("SGS_LEFT %u %08X\n", ntohl(route->segments_left), ntohl(route->segments_left));       DEBUGP("IPv6 RT segsleft %02X ",       		(segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],                           ntohl(route->segments_left),                           !!(rtinfo->invflags & IP6T_RT_INV_SGS))));       DEBUGP("type %02X %02X %02X ",       		rtinfo->rt_type, route->type,        		(!(rtinfo->flags & IP6T_RT_TYP) ||                           ((rtinfo->rt_type == route->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 *)route)->bitmap,       		!((rtinfo->flags & IP6T_RT_RES) && (((struct rt0_hdr *)route)->bitmap)));       ret = (route != NULL)       		&&       		(segsleft_match(rtinfo->segsleft[0], rtinfo->segsleft[1],                           ntohl(route->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 == route->type) ^                           !!(rtinfo->invflags & IP6T_RT_INV_TYP)))		&&       		!((rtinfo->flags & IP6T_RT_RES) && (((struct rt0_hdr *)route)->bitmap));	DEBUGP("#%d ",rtinfo->addrnr);       temp = len = ptr = 0;       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 {			DEBUGP("#%d ",rtinfo->addrnr);			ptr = 0;			for(temp=0; temp<(unsigned int)((hdrlen-8)/16); temp++){				len = 0;				while ((u8)(((struct rt0_hdr *)route)->						addr[temp].s6_addr[len]) ==					(u8)(rtinfo->addrs[ptr].s6_addr[len])){					DEBUGP("%02X?%02X ",		(u8)(((struct rt0_hdr *)route)->addr[temp].s6_addr[len]),					(u8)(rtinfo->addrs[ptr].s6_addr[len]));					len++;					if ( len == 16 ) break;				}				if (len==16) {					DEBUGP("ptr=%d temp=%d;\n",ptr,temp);					ptr++;				} else {					DEBUGP("%02X?%02X ",		(u8)(((struct rt0_hdr *)route)->addr[temp].s6_addr[len]),					(u8)(rtinfo->addrs[ptr].s6_addr[len]));					DEBUGP("!ptr=%d temp=%d;\n",ptr,temp);				}				if (ptr==rtinfo->addrnr) break;			}			DEBUGP("ptr=%d len=%d #%d\n",ptr,len, rtinfo->addrnr);			if ( (len == 16) && (ptr == 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++){				len = 0;				while ((u8)(((struct rt0_hdr *)route)->						addr[temp].s6_addr[len]) ==					(u8)(rtinfo->addrs[temp].s6_addr[len])){					DEBUGP("%02X?%02X ",		(u8)(((struct rt0_hdr *)route)->addr[temp].s6_addr[len]),					(u8)(rtinfo->addrs[temp].s6_addr[len]));					len++;					if ( len == 16 ) break;				}				if (len!=16) {					DEBUGP("%02X?%02X ",		(u8)(((struct rt0_hdr *)route)->addr[temp].s6_addr[len]),					(u8)(rtinfo->addrs[temp].s6_addr[len]));					DEBUGP("!len=%d temp=%d;\n",len,temp);					break;				}			}			DEBUGP("temp=%d len=%d #%d\n",temp,len,rtinfo->addrnr);			if ( (len == 16) && (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 intcheckentry(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);