From: Matti Vaittinen Date: Mon, 14 Nov 2011 00:15:14 +0000 (+0000) Subject: IPv6 routing, NLM_F_* flag support: REPLACE and EXCL flags support, warn about missin... X-Git-Tag: next-20111115~35^2~2 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=4a287eba2;p=karo-tx-linux.git IPv6 routing, NLM_F_* flag support: REPLACE and EXCL flags support, warn about missing CREATE flag The support for NLM_F_* flags at IPv6 routing requests. If NLM_F_CREATE flag is not defined for RTM_NEWROUTE request, warning is printed, but no error is returned. Instead new route is added. Later NLM_F_CREATE may be required for new route creation. Exception is when NLM_F_REPLACE flag is given without NLM_F_CREATE, and no matching route is found. In this case it should be safe to assume that the request issuer is familiar with NLM_F_* flags, and does really not want route to be created. Specifying NLM_F_REPLACE flag will now make the kernel to search for matching route, and replace it with new one. If no route is found and NLM_F_CREATE is specified as well, then new route is created. Also, specifying NLM_F_EXCL will yield returning of error if matching route is found. Patch created against linux-3.2-rc1 Signed-off-by: Matti Vaittinen Signed-off-by: David S. Miller --- diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 93718f3db79b..9239d559b41b 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -425,7 +425,8 @@ out: static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr, int addrlen, int plen, - int offset) + int offset, int allow_create, + int replace_required) { struct fib6_node *fn, *in, *ln; struct fib6_node *pn = NULL; @@ -447,8 +448,12 @@ static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr, * Prefix match */ if (plen < fn->fn_bit || - !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) + !ipv6_prefix_equal(&key->addr, addr, fn->fn_bit)) { + if (!allow_create) + printk(KERN_WARNING + "IPv6: NLM_F_CREATE should be set when creating new route\n"); goto insert_above; + } /* * Exact match ? @@ -477,10 +482,26 @@ static struct fib6_node * fib6_add_1(struct fib6_node *root, void *addr, fn = dir ? fn->right: fn->left; } while (fn); + if (replace_required && !allow_create) { + /* We should not create new node because + * NLM_F_REPLACE was specified without NLM_F_CREATE + * I assume it is safe to require NLM_F_CREATE when + * REPLACE flag is used! Later we may want to remove the + * check for replace_required, because according + * to netlink specification, NLM_F_CREATE + * MUST be specified if new route is created. + * That would keep IPv6 consistent with IPv4 + */ + printk(KERN_WARNING + "IPv6: NLM_F_CREATE should be set when creating new route - ignoring request\n"); + return ERR_PTR(-ENOENT); + } /* * We walked to the bottom of tree. * Create new leaf node without children. */ + if (!allow_create) + printk(KERN_WARNING "IPv6: NLM_F_CREATE should be set when creating new route\n"); ln = node_alloc(); @@ -614,6 +635,12 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, { struct rt6_info *iter = NULL; struct rt6_info **ins; + int replace = (NULL != info && + NULL != info->nlh && + (info->nlh->nlmsg_flags&NLM_F_REPLACE)); + int add = ((NULL == info || NULL == info->nlh) || + (info->nlh->nlmsg_flags&NLM_F_CREATE)); + int found = 0; ins = &fn->leaf; @@ -626,6 +653,13 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, /* * Same priority level */ + if (NULL != info->nlh && + (info->nlh->nlmsg_flags&NLM_F_EXCL)) + return -EEXIST; + if (replace) { + found++; + break; + } if (iter->rt6i_dev == rt->rt6i_dev && iter->rt6i_idev == rt->rt6i_idev && @@ -655,17 +689,40 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt, /* * insert node */ + if (!replace) { + if (!add) + printk(KERN_WARNING "IPv6: NLM_F_CREATE should be set when creating new route\n"); + +add: + rt->dst.rt6_next = iter; + *ins = rt; + rt->rt6i_node = fn; + atomic_inc(&rt->rt6i_ref); + inet6_rt_notify(RTM_NEWROUTE, rt, info); + info->nl_net->ipv6.rt6_stats->fib_rt_entries++; + + if ((fn->fn_flags & RTN_RTINFO) == 0) { + info->nl_net->ipv6.rt6_stats->fib_route_nodes++; + fn->fn_flags |= RTN_RTINFO; + } - rt->dst.rt6_next = iter; - *ins = rt; - rt->rt6i_node = fn; - atomic_inc(&rt->rt6i_ref); - inet6_rt_notify(RTM_NEWROUTE, rt, info); - info->nl_net->ipv6.rt6_stats->fib_rt_entries++; - - if ((fn->fn_flags & RTN_RTINFO) == 0) { - info->nl_net->ipv6.rt6_stats->fib_route_nodes++; - fn->fn_flags |= RTN_RTINFO; + } else { + if (!found) { + if (add) + goto add; + printk(KERN_WARNING "IPv6: NLM_F_REPLACE set, but no existing node found!\n"); + return -ENOENT; + } + *ins = rt; + rt->rt6i_node = fn; + rt->dst.rt6_next = iter->dst.rt6_next; + atomic_inc(&rt->rt6i_ref); + inet6_rt_notify(RTM_NEWROUTE, rt, info); + rt6_release(iter); + if ((fn->fn_flags & RTN_RTINFO) == 0) { + info->nl_net->ipv6.rt6_stats->fib_route_nodes++; + fn->fn_flags |= RTN_RTINFO; + } } return 0; @@ -696,9 +753,25 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info) { struct fib6_node *fn, *pn = NULL; int err = -ENOMEM; + int allow_create = 1; + int replace_required = 0; + if (NULL != info && NULL != info->nlh) { + if (!(info->nlh->nlmsg_flags&NLM_F_CREATE)) + allow_create = 0; + if ((info->nlh->nlmsg_flags&NLM_F_REPLACE)) + replace_required = 1; + } + if (!allow_create && !replace_required) + printk(KERN_WARNING "IPv6: RTM_NEWROUTE with no NLM_F_CREATE or NLM_F_REPLACE\n"); fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr), - rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst)); + rt->rt6i_dst.plen, offsetof(struct rt6_info, rt6i_dst), + allow_create, replace_required); + + if (IS_ERR(fn)) { + err = PTR_ERR(fn); + fn = NULL; + } if (fn == NULL) goto out; @@ -736,7 +809,8 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info) sn = fib6_add_1(sfn, &rt->rt6i_src.addr, sizeof(struct in6_addr), rt->rt6i_src.plen, - offsetof(struct rt6_info, rt6i_src)); + offsetof(struct rt6_info, rt6i_src), + allow_create, replace_required); if (sn == NULL) { /* If it is failed, discard just allocated @@ -753,8 +827,13 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info) } else { sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr, sizeof(struct in6_addr), rt->rt6i_src.plen, - offsetof(struct rt6_info, rt6i_src)); + offsetof(struct rt6_info, rt6i_src), + allow_create, replace_required); + if (IS_ERR(sn)) { + err = PTR_ERR(sn); + sn = NULL; + } if (sn == NULL) goto st_failure; }