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[IPV6]: RFC3484 compliant source address selection
Choose more appropriate source address; e.g. - outgoing interface - non-deprecated - scope - matching label Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
YOSHIFUJI Hideaki
David S. Miller
parent
b1cacb6820
commit
072047e4de
@ -809,138 +809,274 @@ out:
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#endif
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/*
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* Choose an appropriate source address
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* should do:
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* i) get an address with an appropriate scope
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* ii) see if there is a specific route for the destination and use
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* an address of the attached interface
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* iii) don't use deprecated addresses
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* Choose an appropriate source address (RFC3484)
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*/
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static int inline ipv6_saddr_pref(const struct inet6_ifaddr *ifp, u8 invpref)
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struct ipv6_saddr_score {
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int addr_type;
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unsigned int attrs;
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int matchlen;
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unsigned int scope;
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unsigned int rule;
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};
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#define IPV6_SADDR_SCORE_LOCAL 0x0001
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#define IPV6_SADDR_SCORE_PREFERRED 0x0004
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#define IPV6_SADDR_SCORE_HOA 0x0008
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#define IPV6_SADDR_SCORE_OIF 0x0010
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#define IPV6_SADDR_SCORE_LABEL 0x0020
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#define IPV6_SADDR_SCORE_PRIVACY 0x0040
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static int inline ipv6_saddr_preferred(int type)
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{
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int pref;
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pref = ifp->flags&IFA_F_DEPRECATED ? 0 : 2;
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#ifdef CONFIG_IPV6_PRIVACY
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pref |= (ifp->flags^invpref)&IFA_F_TEMPORARY ? 0 : 1;
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#endif
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return pref;
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if (type & (IPV6_ADDR_MAPPED|IPV6_ADDR_COMPATv4|
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IPV6_ADDR_LOOPBACK|IPV6_ADDR_RESERVED))
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return 1;
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return 0;
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}
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#ifdef CONFIG_IPV6_PRIVACY
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#define IPV6_GET_SADDR_MAXSCORE(score) ((score) == 3)
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#else
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#define IPV6_GET_SADDR_MAXSCORE(score) (score)
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#endif
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/* static matching label */
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static int inline ipv6_saddr_label(const struct in6_addr *addr, int type)
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{
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/*
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* prefix (longest match) label
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* -----------------------------
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* ::1/128 0
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* ::/0 1
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* 2002::/16 2
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* ::/96 3
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* ::ffff:0:0/96 4
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*/
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if (type & IPV6_ADDR_LOOPBACK)
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return 0;
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else if (type & IPV6_ADDR_COMPATv4)
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return 3;
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else if (type & IPV6_ADDR_MAPPED)
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return 4;
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else if (addr->s6_addr16[0] == htons(0x2002))
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return 2;
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return 1;
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}
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int ipv6_dev_get_saddr(struct net_device *dev,
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int ipv6_dev_get_saddr(struct net_device *daddr_dev,
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struct in6_addr *daddr, struct in6_addr *saddr)
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{
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struct inet6_ifaddr *ifp = NULL;
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struct inet6_ifaddr *match = NULL;
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struct inet6_dev *idev;
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int scope;
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int err;
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int hiscore = -1, score;
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struct ipv6_saddr_score hiscore;
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struct inet6_ifaddr *ifa_result = NULL;
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int daddr_type = __ipv6_addr_type(daddr);
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int daddr_scope = __ipv6_addr_src_scope(daddr_type);
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u32 daddr_label = ipv6_saddr_label(daddr, daddr_type);
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struct net_device *dev;
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scope = ipv6_addr_scope(daddr);
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/*
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* known dev
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* search dev and walk through dev addresses
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*/
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if (dev) {
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if (dev->flags & IFF_LOOPBACK)
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scope = IFA_HOST;
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read_lock(&addrconf_lock);
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idev = __in6_dev_get(dev);
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if (idev) {
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read_lock_bh(&idev->lock);
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for (ifp=idev->addr_list; ifp; ifp=ifp->if_next) {
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if (ifp->scope == scope) {
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if (ifp->flags&IFA_F_TENTATIVE)
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continue;
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#ifdef CONFIG_IPV6_PRIVACY
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score = ipv6_saddr_pref(ifp, idev->cnf.use_tempaddr > 1 ? IFA_F_TEMPORARY : 0);
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#else
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score = ipv6_saddr_pref(ifp, 0);
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#endif
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if (score <= hiscore)
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continue;
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if (match)
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in6_ifa_put(match);
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match = ifp;
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hiscore = score;
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in6_ifa_hold(ifp);
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if (IPV6_GET_SADDR_MAXSCORE(score)) {
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read_unlock_bh(&idev->lock);
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read_unlock(&addrconf_lock);
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goto out;
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}
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}
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}
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read_unlock_bh(&idev->lock);
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}
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read_unlock(&addrconf_lock);
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}
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if (scope == IFA_LINK)
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goto out;
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/*
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* dev == NULL or search failed for specified dev
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*/
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memset(&hiscore, 0, sizeof(hiscore));
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read_lock(&dev_base_lock);
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read_lock(&addrconf_lock);
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for (dev = dev_base; dev; dev=dev->next) {
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struct inet6_dev *idev;
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struct inet6_ifaddr *ifa;
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/* Rule 0: Candidate Source Address (section 4)
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* - multicast and link-local destination address,
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* the set of candidate source address MUST only
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* include addresses assigned to interfaces
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* belonging to the same link as the outgoing
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* interface.
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* (- For site-local destination addresses, the
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* set of candidate source addresses MUST only
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* include addresses assigned to interfaces
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* belonging to the same site as the outgoing
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* interface.)
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*/
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if ((daddr_type & IPV6_ADDR_MULTICAST ||
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daddr_scope <= IPV6_ADDR_SCOPE_LINKLOCAL) &&
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daddr_dev && dev != daddr_dev)
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continue;
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idev = __in6_dev_get(dev);
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if (idev) {
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read_lock_bh(&idev->lock);
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for (ifp=idev->addr_list; ifp; ifp=ifp->if_next) {
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if (ifp->scope == scope) {
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if (ifp->flags&IFA_F_TENTATIVE)
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continue;
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#ifdef CONFIG_IPV6_PRIVACY
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score = ipv6_saddr_pref(ifp, idev->cnf.use_tempaddr > 1 ? IFA_F_TEMPORARY : 0);
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#else
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score = ipv6_saddr_pref(ifp, 0);
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#endif
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if (score <= hiscore)
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continue;
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if (!idev)
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continue;
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if (match)
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in6_ifa_put(match);
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match = ifp;
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hiscore = score;
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in6_ifa_hold(ifp);
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read_lock_bh(&idev->lock);
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for (ifa = idev->addr_list; ifa; ifa = ifa->if_next) {
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struct ipv6_saddr_score score;
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if (IPV6_GET_SADDR_MAXSCORE(score)) {
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read_unlock_bh(&idev->lock);
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goto out_unlock_base;
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}
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score.addr_type = __ipv6_addr_type(&ifa->addr);
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/* Rule 0: Candidate Source Address (section 4)
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* - In any case, anycast addresses, multicast
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* addresses, and the unspecified address MUST
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* NOT be included in a candidate set.
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*/
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if (unlikely(score.addr_type == IPV6_ADDR_ANY ||
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score.addr_type & IPV6_ADDR_MULTICAST)) {
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LIMIT_NETDEBUG(KERN_DEBUG
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"ADDRCONF: unspecified / multicast address"
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"assigned as unicast address on %s",
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dev->name);
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continue;
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}
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score.attrs = 0;
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score.matchlen = 0;
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score.scope = 0;
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score.rule = 0;
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if (ifa_result == NULL) {
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/* record it if the first available entry */
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goto record_it;
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}
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/* Rule 1: Prefer same address */
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if (hiscore.rule < 1) {
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if (ipv6_addr_equal(&ifa_result->addr, daddr))
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hiscore.attrs |= IPV6_SADDR_SCORE_LOCAL;
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hiscore.rule++;
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}
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if (ipv6_addr_equal(&ifa->addr, daddr)) {
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score.attrs |= IPV6_SADDR_SCORE_LOCAL;
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if (!(hiscore.attrs & IPV6_SADDR_SCORE_LOCAL)) {
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score.rule = 1;
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goto record_it;
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}
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} else {
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if (hiscore.attrs & IPV6_SADDR_SCORE_LOCAL)
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continue;
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}
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/* Rule 2: Prefer appropriate scope */
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if (hiscore.rule < 2) {
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hiscore.scope = __ipv6_addr_src_scope(hiscore.addr_type);
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hiscore.rule++;
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}
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score.scope = __ipv6_addr_src_scope(score.addr_type);
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if (hiscore.scope < score.scope) {
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if (hiscore.scope < daddr_scope) {
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score.rule = 2;
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goto record_it;
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} else
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continue;
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} else if (score.scope < hiscore.scope) {
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if (score.scope < daddr_scope)
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continue;
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else {
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score.rule = 2;
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goto record_it;
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}
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}
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read_unlock_bh(&idev->lock);
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}
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}
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out_unlock_base:
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/* Rule 3: Avoid deprecated address */
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if (hiscore.rule < 3) {
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if (ipv6_saddr_preferred(hiscore.addr_type) ||
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!(ifa_result->flags & IFA_F_DEPRECATED))
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hiscore.attrs |= IPV6_SADDR_SCORE_PREFERRED;
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hiscore.rule++;
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}
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if (ipv6_saddr_preferred(score.addr_type) ||
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!(ifa->flags & IFA_F_DEPRECATED)) {
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score.attrs |= IPV6_SADDR_SCORE_PREFERRED;
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if (!(hiscore.attrs & IPV6_SADDR_SCORE_PREFERRED)) {
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score.rule = 3;
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goto record_it;
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}
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} else {
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if (hiscore.attrs & IPV6_SADDR_SCORE_PREFERRED)
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continue;
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}
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/* Rule 4: Prefer home address -- not implemented yet */
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/* Rule 5: Prefer outgoing interface */
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if (hiscore.rule < 5) {
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if (daddr_dev == NULL ||
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daddr_dev == ifa_result->idev->dev)
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hiscore.attrs |= IPV6_SADDR_SCORE_OIF;
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hiscore.rule++;
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}
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if (daddr_dev == NULL ||
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daddr_dev == ifa->idev->dev) {
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score.attrs |= IPV6_SADDR_SCORE_OIF;
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if (!(hiscore.attrs & IPV6_SADDR_SCORE_OIF)) {
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score.rule = 5;
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goto record_it;
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}
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} else {
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if (hiscore.attrs & IPV6_SADDR_SCORE_OIF)
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continue;
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}
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/* Rule 6: Prefer matching label */
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if (hiscore.rule < 6) {
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if (ipv6_saddr_label(&ifa_result->addr, hiscore.addr_type) == daddr_label)
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hiscore.attrs |= IPV6_SADDR_SCORE_LABEL;
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hiscore.rule++;
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}
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if (ipv6_saddr_label(&ifa->addr, score.addr_type) == daddr_label) {
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score.attrs |= IPV6_SADDR_SCORE_LABEL;
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if (!(hiscore.attrs & IPV6_SADDR_SCORE_LABEL)) {
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score.rule = 6;
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goto record_it;
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}
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} else {
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if (hiscore.attrs & IPV6_SADDR_SCORE_LABEL)
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continue;
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}
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/* Rule 7: Prefer public address
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* Note: prefer temprary address if use_tempaddr >= 2
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*/
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if (hiscore.rule < 7) {
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if ((!(ifa_result->flags & IFA_F_TEMPORARY)) ^
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(ifa_result->idev->cnf.use_tempaddr >= 2))
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hiscore.attrs |= IPV6_SADDR_SCORE_PRIVACY;
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hiscore.rule++;
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}
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if ((!(ifa->flags & IFA_F_TEMPORARY)) ^
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(ifa->idev->cnf.use_tempaddr >= 2)) {
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score.attrs |= IPV6_SADDR_SCORE_PRIVACY;
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if (!(hiscore.attrs & IPV6_SADDR_SCORE_PRIVACY)) {
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score.rule = 7;
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goto record_it;
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}
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} else {
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if (hiscore.attrs & IPV6_SADDR_SCORE_PRIVACY)
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continue;
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}
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/* Rule 8: Use longest matching prefix */
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if (hiscore.rule < 8)
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hiscore.matchlen = ipv6_addr_diff(&ifa_result->addr, daddr);
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score.rule++;
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score.matchlen = ipv6_addr_diff(&ifa->addr, daddr);
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if (score.matchlen > hiscore.matchlen) {
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score.rule = 8;
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goto record_it;
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}
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#if 0
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else if (score.matchlen < hiscore.matchlen)
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continue;
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#endif
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/* Final Rule: choose first available one */
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continue;
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record_it:
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if (ifa_result)
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in6_ifa_put(ifa_result);
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in6_ifa_hold(ifa);
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ifa_result = ifa;
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hiscore = score;
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}
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read_unlock_bh(&idev->lock);
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}
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read_unlock(&addrconf_lock);
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read_unlock(&dev_base_lock);
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out:
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err = -EADDRNOTAVAIL;
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if (match) {
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ipv6_addr_copy(saddr, &match->addr);
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err = 0;
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in6_ifa_put(match);
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}
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return err;
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if (!ifa_result)
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return -EADDRNOTAVAIL;
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ipv6_addr_copy(saddr, &ifa_result->addr);
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in6_ifa_put(ifa_result);
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return 0;
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}
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