From d90ebcbfa7f5a8b4e20518c9f94c5c4e4cd3c2e5 Mon Sep 17 00:00:00 2001 From: Gerrit Renker Date: Wed, 12 Nov 2008 00:47:26 -0800 Subject: dccp: Query supported CCIDs This provides a data structure to record which CCIDs are locally supported and three accessor functions: - a test function for internal use which is used to validate CCID requests made by the user; - a copy function so that the list can be used for feature-negotiation; - documented getsockopt() support so that the user can query capabilities. The data structure is a table which is filled in at compile-time with the list of available CCIDs (which in turn depends on the Kconfig choices). Using the copy function for cloning the list of supported CCIDs is useful for feature negotiation, since the negotiation is now with the full list of available CCIDs (e.g. {2, 3}) instead of the default value {2}. This means negotiation will not fail if the peer requests to use CCID3 instead of CCID2. Signed-off-by: Gerrit Renker Acked-by: Ian McDonald Signed-off-by: David S. Miller --- net/dccp/ccid.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ net/dccp/ccid.h | 5 +++++ net/dccp/feat.c | 4 ++++ net/dccp/proto.c | 2 ++ 4 files changed, 59 insertions(+) (limited to 'net') diff --git a/net/dccp/ccid.c b/net/dccp/ccid.c index 8fe931a3d7a1..647cb0614f84 100644 --- a/net/dccp/ccid.c +++ b/net/dccp/ccid.c @@ -13,6 +13,13 @@ #include "ccid.h" +static u8 builtin_ccids[] = { + DCCPC_CCID2, /* CCID2 is supported by default */ +#if defined(CONFIG_IP_DCCP_CCID3) || defined(CONFIG_IP_DCCP_CCID3_MODULE) + DCCPC_CCID3, +#endif +}; + static struct ccid_operations *ccids[CCID_MAX]; #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) static atomic_t ccids_lockct = ATOMIC_INIT(0); @@ -86,6 +93,47 @@ static void ccid_kmem_cache_destroy(struct kmem_cache *slab) } } +/* check that up to @array_len members in @ccid_array are supported */ +bool ccid_support_check(u8 const *ccid_array, u8 array_len) +{ + u8 i, j, found; + + for (i = 0, found = 0; i < array_len; i++, found = 0) { + for (j = 0; !found && j < ARRAY_SIZE(builtin_ccids); j++) + found = (ccid_array[i] == builtin_ccids[j]); + if (!found) + return false; + } + return true; +} + +/** + * ccid_get_builtin_ccids - Provide copy of `builtin' CCID array + * @ccid_array: pointer to copy into + * @array_len: value to return length into + * This function allocates memory - caller must see that it is freed after use. + */ +int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len) +{ + *ccid_array = kmemdup(builtin_ccids, sizeof(builtin_ccids), gfp_any()); + if (*ccid_array == NULL) + return -ENOBUFS; + *array_len = ARRAY_SIZE(builtin_ccids); + return 0; +} + +int ccid_getsockopt_builtin_ccids(struct sock *sk, int len, + char __user *optval, int __user *optlen) +{ + if (len < sizeof(builtin_ccids)) + return -EINVAL; + + if (put_user(sizeof(builtin_ccids), optlen) || + copy_to_user(optval, builtin_ccids, sizeof(builtin_ccids))) + return -EFAULT; + return 0; +} + int ccid_register(struct ccid_operations *ccid_ops) { int err = -ENOBUFS; diff --git a/net/dccp/ccid.h b/net/dccp/ccid.h index fdeae7b57319..259f5469d7d0 100644 --- a/net/dccp/ccid.h +++ b/net/dccp/ccid.h @@ -103,6 +103,11 @@ static inline void *ccid_priv(const struct ccid *ccid) return (void *)ccid->ccid_priv; } +extern bool ccid_support_check(u8 const *ccid_array, u8 array_len); +extern int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len); +extern int ccid_getsockopt_builtin_ccids(struct sock *sk, int len, + char __user *, int __user *); + extern struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx, gfp_t gfp); diff --git a/net/dccp/feat.c b/net/dccp/feat.c index 192d494a3816..f79fb5e33f5e 100644 --- a/net/dccp/feat.c +++ b/net/dccp/feat.c @@ -342,6 +342,10 @@ static int __feat_register_sp(struct list_head *fn, u8 feat, u8 is_local, !dccp_feat_sp_list_ok(feat, sp_val, sp_len)) return -EINVAL; + /* Avoid negotiating alien CCIDs by only advertising supported ones */ + if (feat == DCCPF_CCID && !ccid_support_check(sp_val, sp_len)) + return -EOPNOTSUPP; + if (dccp_feat_clone_sp_val(&fval, sp_val, sp_len)) return -ENOMEM; diff --git a/net/dccp/proto.c b/net/dccp/proto.c index 01332fe7a99a..b4b10cbd8880 100644 --- a/net/dccp/proto.c +++ b/net/dccp/proto.c @@ -649,6 +649,8 @@ static int do_dccp_getsockopt(struct sock *sk, int level, int optname, case DCCP_SOCKOPT_GET_CUR_MPS: val = dp->dccps_mss_cache; break; + case DCCP_SOCKOPT_AVAILABLE_CCIDS: + return ccid_getsockopt_builtin_ccids(sk, len, optval, optlen); case DCCP_SOCKOPT_SERVER_TIMEWAIT: val = dp->dccps_server_timewait; break; -- cgit v1.2.3