6dfac5c336
First off, we don't need to check for non-NULL rt any more, as we are guaranteed to always get a valid rt6_info. Drop the check. In case we couldn't allocate an inet_peer for fragmentation information we currently generate strictly incrementing fragmentation ids for all destination. This is done to maximize the cycle and avoid collisions. Those fragmentation ids are very predictable. At least we should try to mix in the destination address. While it should make no difference to simply use a PRNG at this point, secure_ipv6_id ensures that we don't leak information from prandom, so its internal state could be recoverable. This fallback function should normally not get used thus this should not affect performance at all. It is just meant as a safety net. Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
129 lines
2.8 KiB
C
129 lines
2.8 KiB
C
/*
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* IPv6 library code, needed by static components when full IPv6 support is
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* not configured or static. These functions are needed by GSO/GRO implementation.
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*/
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#include <linux/export.h>
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#include <net/ipv6.h>
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#include <net/ip6_fib.h>
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#include <net/addrconf.h>
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#include <net/secure_seq.h>
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void ipv6_select_ident(struct frag_hdr *fhdr, struct rt6_info *rt)
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{
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static atomic_t ipv6_fragmentation_id;
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struct in6_addr addr;
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int old, new;
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#if IS_ENABLED(CONFIG_IPV6)
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struct inet_peer *peer;
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struct net *net;
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net = dev_net(rt->dst.dev);
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peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, 1);
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if (peer) {
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fhdr->identification = htonl(inet_getid(peer, 0));
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inet_putpeer(peer);
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return;
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}
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#endif
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do {
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old = atomic_read(&ipv6_fragmentation_id);
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new = old + 1;
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if (!new)
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new = 1;
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} while (atomic_cmpxchg(&ipv6_fragmentation_id, old, new) != old);
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addr = rt->rt6i_dst.addr;
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addr.s6_addr32[0] ^= (__force __be32)new;
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fhdr->identification = htonl(secure_ipv6_id(addr.s6_addr32));
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}
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EXPORT_SYMBOL(ipv6_select_ident);
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int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
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{
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u16 offset = sizeof(struct ipv6hdr);
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struct ipv6_opt_hdr *exthdr =
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(struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1);
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unsigned int packet_len = skb_tail_pointer(skb) -
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skb_network_header(skb);
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int found_rhdr = 0;
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*nexthdr = &ipv6_hdr(skb)->nexthdr;
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while (offset + 1 <= packet_len) {
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switch (**nexthdr) {
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case NEXTHDR_HOP:
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break;
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case NEXTHDR_ROUTING:
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found_rhdr = 1;
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break;
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case NEXTHDR_DEST:
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#if IS_ENABLED(CONFIG_IPV6_MIP6)
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if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0)
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break;
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#endif
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if (found_rhdr)
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return offset;
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break;
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default :
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return offset;
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}
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offset += ipv6_optlen(exthdr);
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*nexthdr = &exthdr->nexthdr;
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exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
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offset);
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}
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return offset;
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}
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EXPORT_SYMBOL(ip6_find_1stfragopt);
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#if IS_ENABLED(CONFIG_IPV6)
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int ip6_dst_hoplimit(struct dst_entry *dst)
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{
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int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
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if (hoplimit == 0) {
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struct net_device *dev = dst->dev;
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struct inet6_dev *idev;
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rcu_read_lock();
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idev = __in6_dev_get(dev);
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if (idev)
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hoplimit = idev->cnf.hop_limit;
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else
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hoplimit = dev_net(dev)->ipv6.devconf_all->hop_limit;
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rcu_read_unlock();
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}
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return hoplimit;
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}
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EXPORT_SYMBOL(ip6_dst_hoplimit);
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#endif
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int __ip6_local_out(struct sk_buff *skb)
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{
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int len;
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len = skb->len - sizeof(struct ipv6hdr);
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if (len > IPV6_MAXPLEN)
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len = 0;
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ipv6_hdr(skb)->payload_len = htons(len);
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return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
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skb_dst(skb)->dev, dst_output);
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}
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EXPORT_SYMBOL_GPL(__ip6_local_out);
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int ip6_local_out(struct sk_buff *skb)
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{
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int err;
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err = __ip6_local_out(skb);
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if (likely(err == 1))
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err = dst_output(skb);
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return err;
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}
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EXPORT_SYMBOL_GPL(ip6_local_out);
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