From 0ab43f84995f2c2fcc5cc58a9accaa1095e1317f Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Tue, 9 Aug 2005 19:43:44 -0700 Subject: [PATCH] [NETFILTER]: Core changes required by upcoming nfnetlink_queue code - split netfiler verdict in 16bit verdict and 16bit queue number - add 'queuenum' argument to nf_queue_outfn_t and its users ip[6]_queue - move NFNL_SUBSYS_ definitions from enum to #define - introduce autoloading for nfnetlink subsystem modules - add MODULE_ALIAS_NFNL_SUBSYS macro - add nf_unregister_queue_handlers() to register all handlers for a given nf_queue_outfn_t - add more verbose DEBUGP macro definition to nfnetlink.c - make nfnetlink_subsys_register fail if subsys already exists - add some more comments and debug statements to nfnetlink.c Signed-off-by: Harald Welte Signed-off-by: David S. Miller --- include/linux/netfilter.h | 14 +++++++++- include/linux/netfilter/nfnetlink.h | 20 ++++++++------- net/core/netfilter.c | 40 ++++++++++++++++++++++++----- net/ipv4/netfilter/ip_queue.c | 3 ++- net/ipv6/netfilter/ip6_queue.c | 3 ++- net/netfilter/nfnetlink.c | 28 +++++++++++++++----- 6 files changed, 83 insertions(+), 25 deletions(-) diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index d163e20ca8d9..711e05f33d68 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -21,6 +21,16 @@ #define NF_STOP 5 #define NF_MAX_VERDICT NF_STOP +/* we overload the higher bits for encoding auxiliary data such as the queue + * number. Not nice, but better than additional function arguments. */ +#define NF_VERDICT_MASK 0x0000ffff +#define NF_VERDICT_BITS 16 + +#define NF_VERDICT_QMASK 0xffff0000 +#define NF_VERDICT_QBITS 16 + +#define NF_QUEUE_NR(x) ((x << NF_VERDICT_QBITS) & NF_VERDICT_QMASK || NF_QUEUE) + /* only for userspace compatibility */ #ifndef __KERNEL__ /* Generic cache responses from hook functions. @@ -179,10 +189,12 @@ int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt, /* Packet queuing */ typedef int (*nf_queue_outfn_t)(struct sk_buff *skb, - struct nf_info *info, void *data); + struct nf_info *info, + unsigned int queuenum, void *data); extern int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data); extern int nf_unregister_queue_handler(int pf); +extern void nf_unregister_queue_handlers(nf_queue_outfn_t outfn); extern void nf_reinject(struct sk_buff *skb, struct nf_info *info, unsigned int verdict); diff --git a/include/linux/netfilter/nfnetlink.h b/include/linux/netfilter/nfnetlink.h index ace7a7be0742..561f9df28808 100644 --- a/include/linux/netfilter/nfnetlink.h +++ b/include/linux/netfilter/nfnetlink.h @@ -69,15 +69,14 @@ struct nfgenmsg { #define NFNL_SUBSYS_ID(x) ((x & 0xff00) >> 8) #define NFNL_MSG_TYPE(x) (x & 0x00ff) -enum nfnl_subsys_id { - NFNL_SUBSYS_NONE = 0, - NFNL_SUBSYS_CTNETLINK, - NFNL_SUBSYS_CTNETLINK_EXP, - NFNL_SUBSYS_IPTNETLINK, - NFNL_SUBSYS_QUEUE, - NFNL_SUBSYS_ULOG, - NFNL_SUBSYS_COUNT, -}; +/* No enum here, otherwise __stringify() trick of MODULE_ALIAS_NFNL_SUBSYS() + * won't work anymore */ +#define NFNL_SUBSYS_NONE 0 +#define NFNL_SUBSYS_CTNETLINK 1 +#define NFNL_SUBSYS_CTNETLINK_EXP 2 +#define NFNL_SUBSYS_QUEUE 3 +#define NFNL_SUBSYS_ULOG 4 +#define NFNL_SUBSYS_COUNT 5 #ifdef __KERNEL__ @@ -142,5 +141,8 @@ extern int nfnetlink_send(struct sk_buff *skb, u32 pid, unsigned group, int echo); extern int nfnetlink_unicast(struct sk_buff *skb, u_int32_t pid, int flags); +#define MODULE_ALIAS_NFNL_SUBSYS(subsys) \ + MODULE_ALIAS("nfnetlink-subsys-" __stringify(subsys)) + #endif /* __KERNEL__ */ #endif /* _NFNETLINK_H */ diff --git a/net/core/netfilter.c b/net/core/netfilter.c index 1ed4f3110421..3e38084ac2bd 100644 --- a/net/core/netfilter.c +++ b/net/core/netfilter.c @@ -221,7 +221,8 @@ static unsigned int nf_iterate(struct list_head *head, verdict = elem->hook(hook, skb, indev, outdev, okfn); if (verdict != NF_ACCEPT) { #ifdef CONFIG_NETFILTER_DEBUG - if (unlikely(verdict > NF_MAX_VERDICT)) { + if (unlikely((verdict & NF_VERDICT_MASK) + > NF_MAX_VERDICT)) { NFDEBUG("Evil return from %p(%u).\n", elem->hook, hook); continue; @@ -239,6 +240,9 @@ int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data) { int ret; + if (pf >= NPROTO) + return -EINVAL; + write_lock_bh(&queue_handler_lock); if (queue_handler[pf].outfn) ret = -EBUSY; @@ -255,6 +259,9 @@ int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data) /* The caller must flush their queue before this */ int nf_unregister_queue_handler(int pf) { + if (pf >= NPROTO) + return -EINVAL; + write_lock_bh(&queue_handler_lock); queue_handler[pf].outfn = NULL; queue_handler[pf].data = NULL; @@ -286,6 +293,20 @@ int nf_unregister_queue_rerouter(int pf) return 0; } +void nf_unregister_queue_handlers(nf_queue_outfn_t outfn) +{ + int pf; + + write_lock_bh(&queue_handler_lock); + for (pf = 0; pf < NPROTO; pf++) { + if (queue_handler[pf].outfn == outfn) { + queue_handler[pf].outfn = NULL; + queue_handler[pf].data = NULL; + } + } + write_unlock_bh(&queue_handler_lock); +} + /* * Any packet that leaves via this function must come back * through nf_reinject(). @@ -295,7 +316,8 @@ static int nf_queue(struct sk_buff **skb, int pf, unsigned int hook, struct net_device *indev, struct net_device *outdev, - int (*okfn)(struct sk_buff *)) + int (*okfn)(struct sk_buff *), + unsigned int queuenum) { int status; struct nf_info *info; @@ -347,7 +369,8 @@ static int nf_queue(struct sk_buff **skb, if (queue_rerouter[pf].save) queue_rerouter[pf].save(*skb, info); - status = queue_handler[pf].outfn(*skb, info, queue_handler[pf].data); + status = queue_handler[pf].outfn(*skb, info, queuenum, + queue_handler[pf].data); if (status >= 0 && queue_rerouter[pf].reroute) status = queue_rerouter[pf].reroute(skb, info); @@ -397,9 +420,10 @@ next_hook: } else if (verdict == NF_DROP) { kfree_skb(*pskb); ret = -EPERM; - } else if (verdict == NF_QUEUE) { + } else if ((verdict & NF_VERDICT_MASK) == NF_QUEUE) { NFDEBUG("nf_hook: Verdict = QUEUE.\n"); - if (!nf_queue(pskb, elem, pf, hook, indev, outdev, okfn)) + if (!nf_queue(pskb, elem, pf, hook, indev, outdev, okfn, + verdict >> NF_VERDICT_BITS)) goto next_hook; } unlock: @@ -456,14 +480,15 @@ void nf_reinject(struct sk_buff *skb, struct nf_info *info, info->okfn, INT_MIN); } - switch (verdict) { + switch (verdict & NF_VERDICT_MASK) { case NF_ACCEPT: info->okfn(skb); break; case NF_QUEUE: if (!nf_queue(&skb, elem, info->pf, info->hook, - info->indev, info->outdev, info->okfn)) + info->indev, info->outdev, info->okfn, + verdict >> NF_VERDICT_BITS)) goto next_hook; break; } @@ -613,6 +638,7 @@ EXPORT_SYMBOL(nf_reinject); EXPORT_SYMBOL(nf_setsockopt); EXPORT_SYMBOL(nf_unregister_hook); EXPORT_SYMBOL(nf_unregister_queue_handler); +EXPORT_SYMBOL_GPL(nf_unregister_queue_handlers); EXPORT_SYMBOL_GPL(nf_register_queue_rerouter); EXPORT_SYMBOL_GPL(nf_unregister_queue_rerouter); EXPORT_SYMBOL(nf_unregister_sockopt); diff --git a/net/ipv4/netfilter/ip_queue.c b/net/ipv4/netfilter/ip_queue.c index 78892980f42c..cfc886f382ac 100644 --- a/net/ipv4/netfilter/ip_queue.c +++ b/net/ipv4/netfilter/ip_queue.c @@ -280,7 +280,8 @@ nlmsg_failure: } static int -ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data) +ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, + unsigned int queuenum, void *data) { int status = -EINVAL; struct sk_buff *nskb; diff --git a/net/ipv6/netfilter/ip6_queue.c b/net/ipv6/netfilter/ip6_queue.c index c45d8f8815de..5af4cee93d9b 100644 --- a/net/ipv6/netfilter/ip6_queue.c +++ b/net/ipv6/netfilter/ip6_queue.c @@ -278,7 +278,8 @@ nlmsg_failure: } static int -ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, void *data) +ipq_enqueue_packet(struct sk_buff *skb, struct nf_info *info, + unsigned int queuenum, void *data) { int status = -EINVAL; struct sk_buff *nskb; diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c index 6210ca42166c..30b25f47f7cc 100644 --- a/net/netfilter/nfnetlink.c +++ b/net/netfilter/nfnetlink.c @@ -44,7 +44,9 @@ MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_NETFILTER); static char __initdata nfversion[] = "0.30"; #if 0 -#define DEBUGP printk +#define DEBUGP(format, args...) \ + printk(KERN_DEBUG "%s(%d):%s(): " format, __FILE__, \ + __LINE__, __FUNCTION__, ## args) #else #define DEBUGP(format, args...) #endif @@ -67,11 +69,11 @@ int nfnetlink_subsys_register(struct nfnetlink_subsystem *n) { DEBUGP("registering subsystem ID %u\n", n->subsys_id); - /* If the netlink socket wasn't created, then fail */ - if (!nfnl) - return -1; - nfnl_lock(); + if (subsys_table[n->subsys_id]) { + nfnl_unlock(); + return -EBUSY; + } subsys_table[n->subsys_id] = n; nfnl_unlock(); @@ -227,8 +229,18 @@ static inline int nfnetlink_rcv_msg(struct sk_buff *skb, type = nlh->nlmsg_type; ss = nfnetlink_get_subsys(type); - if (!ss) + if (!ss) { +#ifdef CONFIG_KMOD + /* don't call nfnl_shunlock, since it would reenter + * with further packet processing */ + up(&nfnl_sem); + request_module("nfnetlink-subsys-%d", NFNL_SUBSYS_ID(type)); + nfnl_shlock(); + ss = nfnetlink_get_subsys(type); + if (!ss) +#endif goto err_inval; + } nc = nfnetlink_find_client(type, ss); if (!nc) { @@ -252,12 +264,14 @@ static inline int nfnetlink_rcv_msg(struct sk_buff *skb, if (err < 0) goto err_inval; + DEBUGP("calling handler\n"); err = nc->call(nfnl, skb, nlh, cda, errp); *errp = err; return err; } err_inval: + DEBUGP("returning -EINVAL\n"); *errp = -EINVAL; return -1; } @@ -311,6 +325,8 @@ static void nfnetlink_rcv(struct sock *sk, int len) kfree_skb(skb); } + /* don't call nfnl_shunlock, since it would reenter + * with further packet processing */ up(&nfnl_sem); } while(nfnl && nfnl->sk_receive_queue.qlen); } -- 2.39.2