Index: linux-2.4.35.4/net/ipv6/netfilter/ip6t_REJECT.c =================================================================== --- /dev/null +++ linux-2.4.35.4/net/ipv6/netfilter/ip6t_REJECT.c @@ -0,0 +1,301 @@ +/* + * This is a module which is used for rejecting packets. + * Added support for customized reject packets (Jozsef Kadlecsik). + * Sun 12 Nov 2000 + * Port to IPv6 / ip6tables (Harald Welte ) + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#if 1 +#define DEBUGP printk +#else +#define DEBUGP(format, args...) +#endif + +#if 0 +/* Send RST reply */ +static void send_reset(struct sk_buff *oldskb) +{ + struct sk_buff *nskb; + struct tcphdr *otcph, *tcph; + struct rtable *rt; + unsigned int otcplen; + int needs_ack; + + /* IP header checks: fragment, too short. */ + if (oldskb->nh.iph->frag_off & htons(IP_OFFSET) + || oldskb->len < (oldskb->nh.iph->ihl<<2) + sizeof(struct tcphdr)) + return; + + otcph = (struct tcphdr *)((u_int32_t*)oldskb->nh.iph + oldskb->nh.iph->ihl); + otcplen = oldskb->len - oldskb->nh.iph->ihl*4; + + /* No RST for RST. */ + if (otcph->rst) + return; + + /* Check checksum. */ + if (tcp_v4_check(otcph, otcplen, oldskb->nh.iph->saddr, + oldskb->nh.iph->daddr, + csum_partial((char *)otcph, otcplen, 0)) != 0) + return; + + /* Copy skb (even if skb is about to be dropped, we can't just + clone it because there may be other things, such as tcpdump, + interested in it) */ + nskb = skb_copy(oldskb, GFP_ATOMIC); + if (!nskb) + return; + + /* This packet will not be the same as the other: clear nf fields */ + nf_conntrack_put(nskb->nfct); + nskb->nfct = NULL; + nskb->nfcache = 0; +#ifdef CONFIG_NETFILTER_DEBUG + nskb->nf_debug = 0; +#endif + + tcph = (struct tcphdr *)((u_int32_t*)nskb->nh.iph + nskb->nh.iph->ihl); + + nskb->nh.iph->daddr = xchg(&nskb->nh.iph->saddr, nskb->nh.iph->daddr); + tcph->source = xchg(&tcph->dest, tcph->source); + + /* Truncate to length (no data) */ + tcph->doff = sizeof(struct tcphdr)/4; + skb_trim(nskb, nskb->nh.iph->ihl*4 + sizeof(struct tcphdr)); + nskb->nh.iph->tot_len = htons(nskb->len); + + if (tcph->ack) { + needs_ack = 0; + tcph->seq = otcph->ack_seq; + tcph->ack_seq = 0; + } else { + needs_ack = 1; + tcph->ack_seq = htonl(ntohl(otcph->seq) + otcph->syn + otcph->fin + + otcplen - (otcph->doff<<2)); + tcph->seq = 0; + } + + /* Reset flags */ + ((u_int8_t *)tcph)[13] = 0; + tcph->rst = 1; + tcph->ack = needs_ack; + + tcph->window = 0; + tcph->urg_ptr = 0; + + /* Adjust TCP checksum */ + tcph->check = 0; + tcph->check = tcp_v4_check(tcph, sizeof(struct tcphdr), + nskb->nh.iph->saddr, + nskb->nh.iph->daddr, + csum_partial((char *)tcph, + sizeof(struct tcphdr), 0)); + + /* Adjust IP TTL, DF */ + nskb->nh.iph->ttl = MAXTTL; + /* Set DF, id = 0 */ + nskb->nh.iph->frag_off = htons(IP_DF); + nskb->nh.iph->id = 0; + + /* Adjust IP checksum */ + nskb->nh.iph->check = 0; + nskb->nh.iph->check = ip_fast_csum((unsigned char *)nskb->nh.iph, + nskb->nh.iph->ihl); + + /* Routing */ + if (ip_route_output(&rt, nskb->nh.iph->daddr, nskb->nh.iph->saddr, + RT_TOS(nskb->nh.iph->tos) | RTO_CONN, + 0) != 0) + goto free_nskb; + + dst_release(nskb->dst); + nskb->dst = &rt->u.dst; + + /* "Never happens" */ + if (nskb->len > nskb->dst->pmtu) + goto free_nskb; + + NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev, + ip_finish_output); + return; + + free_nskb: + kfree_skb(nskb); +} +#endif + +static unsigned int reject6_target(struct sk_buff **pskb, + unsigned int hooknum, + const struct net_device *in, + const struct net_device *out, + const void *targinfo, + void *userinfo) +{ + const struct ip6t_reject_info *reject = targinfo; + struct sk_buff *skb2 = NULL; + struct rt6_info *rt6i; + struct net_device odev; + + if (!out) { + skb2 = skb_clone(*pskb, GFP_ATOMIC); + if (skb2 == NULL) { + return NF_DROP; + } + dst_release(skb2->dst); + skb2->dst = NULL; + + rt6i = rt6_lookup(&skb2->nh.ipv6h->saddr, NULL, 0, 0); + if (rt6i && rt6i->rt6i_dev) { + skb2->dev = rt6i->rt6i_dev; + rt6i = rt6_lookup(&skb2->nh.ipv6h->daddr, &skb2->nh.ipv6h->saddr, 0, 0); + } + memcpy(&odev, skb2->dev, sizeof(odev)); /* XXX 'out' has 'const' qualifier... */ + } else { + memcpy(&odev, out, sizeof(odev)); + } + + printk(KERN_DEBUG "%s: medium point\n", __FUNCTION__); + /* WARNING: This code causes reentry within ip6tables. + This means that the ip6tables jump stack is now crap. We + must return an absolute verdict. --RR */ + DEBUGP("REJECTv6: calling icmpv6_send\n"); + switch (reject->with) { + case IP6T_ICMP6_NO_ROUTE: + icmpv6_send(*pskb, ICMPV6_DEST_UNREACH, ICMPV6_NOROUTE, 0, &odev); + break; + case IP6T_ICMP6_ADM_PROHIBITED: + icmpv6_send(*pskb, ICMPV6_DEST_UNREACH, ICMPV6_ADM_PROHIBITED, 0, &odev); + break; + case IP6T_ICMP6_NOT_NEIGHBOUR: + icmpv6_send(*pskb, ICMPV6_DEST_UNREACH, ICMPV6_NOT_NEIGHBOUR, 0, &odev); + break; + case IP6T_ICMP6_ADDR_UNREACH: + icmpv6_send(*pskb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0, &odev); + break; + case IP6T_ICMP6_PORT_UNREACH: + icmpv6_send(*pskb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0, &odev); + break; +#if 0 + case IPT_ICMP_ECHOREPLY: { + struct icmp6hdr *icmph = (struct icmphdr *) + ((u_int32_t *)(*pskb)->nh.iph + (*pskb)->nh.iph->ihl); + unsigned int datalen = (*pskb)->len - (*pskb)->nh.iph->ihl * 4; + + /* Not non-head frags, or truncated */ + if (((ntohs((*pskb)->nh.iph->frag_off) & IP_OFFSET) == 0) + && datalen >= 4) { + /* Usually I don't like cut & pasting code, + but dammit, my party is starting in 45 + mins! --RR */ + struct icmp_bxm icmp_param; + + icmp_param.icmph=*icmph; + icmp_param.icmph.type=ICMP_ECHOREPLY; + icmp_param.data_ptr=(icmph+1); + icmp_param.data_len=datalen; + icmp_reply(&icmp_param, *pskb); + } + } + break; + case IPT_TCP_RESET: + send_reset(*pskb); + break; +#endif + default: + printk(KERN_WARNING "REJECTv6: case %u not handled yet\n", reject->with); + break; + } + + if (skb2) kfree_skb(skb2); + + return NF_DROP; +} + +static inline int find_ping_match(const struct ip6t_entry_match *m) +{ + const struct ip6t_icmp *icmpinfo = (const struct ip6t_icmp *)m->data; + + if (strcmp(m->u.kernel.match->name, "icmp6") == 0 + && icmpinfo->type == ICMPV6_ECHO_REQUEST + && !(icmpinfo->invflags & IP6T_ICMP_INV)) + return 1; + + return 0; +} + +static int check(const char *tablename, + const struct ip6t_entry *e, + void *targinfo, + unsigned int targinfosize, + unsigned int hook_mask) +{ + const struct ip6t_reject_info *rejinfo = targinfo; + + if (targinfosize != IP6T_ALIGN(sizeof(struct ip6t_reject_info))) { + DEBUGP("REJECTv6: targinfosize %u != 0\n", targinfosize); + return 0; + } + + /* Only allow these for packet filtering. */ + if (strcmp(tablename, "filter") != 0) { + DEBUGP("REJECTv6: bad table `%s'.\n", tablename); + return 0; + } + if ((hook_mask & ~((1 << NF_IP6_LOCAL_IN) + | (1 << NF_IP6_FORWARD) + | (1 << NF_IP6_LOCAL_OUT))) != 0) { + DEBUGP("REJECTv6: bad hook mask %X\n", hook_mask); + return 0; + } + + if (rejinfo->with == IP6T_ICMP6_ECHOREPLY) { + /* Must specify that it's an ICMP ping packet. */ + if (e->ipv6.proto != IPPROTO_ICMPV6 + || (e->ipv6.invflags & IP6T_INV_PROTO)) { + DEBUGP("REJECTv6: ECHOREPLY illegal for non-icmp\n"); + return 0; + } + /* Must contain ICMP match. */ + if (IP6T_MATCH_ITERATE(e, find_ping_match) == 0) { + DEBUGP("REJECTv6: ECHOREPLY illegal for non-ping\n"); + return 0; + } + } else if (rejinfo->with == IP6T_TCP_RESET) { + /* Must specify that it's a TCP packet */ + if (e->ipv6.proto != IPPROTO_TCP + || (e->ipv6.invflags & IP6T_INV_PROTO)) { + DEBUGP("REJECTv6: TCP_RESET illegal for non-tcp\n"); + return 0; + } + } + + return 1; +} + +static struct ip6t_target ip6t_reject_reg += { { NULL, NULL }, "REJECT", reject6_target, check, NULL, THIS_MODULE }; + +static int __init init(void) +{ + if (ip6t_register_target(&ip6t_reject_reg)) + return -EINVAL; + return 0; +} + +static void __exit fini(void) +{ + ip6t_unregister_target(&ip6t_reject_reg); +} + +module_init(init); +module_exit(fini); Index: linux-2.4.35.4/include/linux/netfilter_ipv6/ip6t_REJECT.h =================================================================== --- linux-2.4.35.4.orig/include/linux/netfilter_ipv6/ip6t_REJECT.h +++ linux-2.4.35.4/include/linux/netfilter_ipv6/ip6t_REJECT.h @@ -2,15 +2,17 @@ #define _IP6T_REJECT_H enum ip6t_reject_with { - IP6T_ICMP_NET_UNREACHABLE, - IP6T_ICMP_HOST_UNREACHABLE, - IP6T_ICMP_PROT_UNREACHABLE, - IP6T_ICMP_PORT_UNREACHABLE, - IP6T_ICMP_ECHOREPLY + IP6T_ICMP6_NO_ROUTE, + IP6T_ICMP6_ADM_PROHIBITED, + IP6T_ICMP6_NOT_NEIGHBOUR, + IP6T_ICMP6_ADDR_UNREACH, + IP6T_ICMP6_PORT_UNREACH, + IP6T_ICMP6_ECHOREPLY, + IP6T_TCP_RESET }; struct ip6t_reject_info { enum ip6t_reject_with with; /* reject type */ }; -#endif /*_IPT_REJECT_H*/ +#endif /*_IP6T_REJECT_H*/ Index: linux-2.4.35.4/net/ipv6/netfilter/Makefile =================================================================== --- linux-2.4.35.4.orig/net/ipv6/netfilter/Makefile +++ linux-2.4.35.4/net/ipv6/netfilter/Makefile @@ -34,5 +34,7 @@ obj-$(CONFIG_IP6_NF_QUEUE) += ip6_queue. obj-$(CONFIG_IP6_NF_TARGET_LOG) += ip6t_LOG.o obj-$(CONFIG_IP6_NF_MATCH_RANDOM) += ip6t_random.o obj-$(CONFIG_IP6_NF_MATCH_HL) += ip6t_hl.o +obj-$(CONFIG_IP6_NF_TARGET_REJECT) += ip6t_REJECT.o + include $(TOPDIR)/Rules.make Index: linux-2.4.35.4/net/ipv6/netfilter/Config.in =================================================================== --- linux-2.4.35.4.orig/net/ipv6/netfilter/Config.in +++ linux-2.4.35.4/net/ipv6/netfilter/Config.in @@ -61,6 +61,9 @@ if [ "$CONFIG_IP6_NF_IPTABLES" != "n" ]; if [ "$CONFIG_IP6_NF_FILTER" != "n" ]; then dep_tristate ' LOG target support' CONFIG_IP6_NF_TARGET_LOG $CONFIG_IP6_NF_FILTER fi + if [ "$CONFIG_IP6_NF_FILTER" != "n" ]; then + dep_tristate ' REJECT target support' CONFIG_IP6_NF_TARGET_REJECT $CONFIG_IP6_NF_FILTER + fi # if [ "$CONFIG_IP6_NF_FILTER" != "n" ]; then # dep_tristate ' REJECT target support' CONFIG_IP6_NF_TARGET_REJECT $CONFIG_IP6_NF_FILTER