diff options
| -rw-r--r-- | include/net/netlink.h | 9 | ||||
| -rw-r--r-- | net/netlink/genetlink.c | 3 | ||||
| -rw-r--r-- | net/netlink/policy.c | 102 |
3 files changed, 90 insertions, 24 deletions
diff --git a/include/net/netlink.h b/include/net/netlink.h index 00258590f2cb..5a5ff97cc596 100644 --- a/include/net/netlink.h +++ b/include/net/netlink.h @@ -1937,9 +1937,12 @@ void nla_get_range_signed(const struct nla_policy *pt, struct netlink_policy_dump_state; -int netlink_policy_dump_start(const struct nla_policy *policy, - unsigned int maxtype, - struct netlink_policy_dump_state **state); +int netlink_policy_dump_add_policy(struct netlink_policy_dump_state **pstate, + const struct nla_policy *policy, + unsigned int maxtype); +int netlink_policy_dump_get_policy_idx(struct netlink_policy_dump_state *state, + const struct nla_policy *policy, + unsigned int maxtype); bool netlink_policy_dump_loop(struct netlink_policy_dump_state *state); int netlink_policy_dump_write(struct sk_buff *skb, struct netlink_policy_dump_state *state); diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 7ddc574931f4..89646b97300c 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -1150,7 +1150,8 @@ static int ctrl_dumppolicy_start(struct netlink_callback *cb) if (!rt->policy) return -ENODATA; - return netlink_policy_dump_start(rt->policy, rt->maxattr, &ctx->state); + return netlink_policy_dump_add_policy(&ctx->state, rt->policy, + rt->maxattr); } static int ctrl_dumppolicy(struct sk_buff *skb, struct netlink_callback *cb) diff --git a/net/netlink/policy.c b/net/netlink/policy.c index 753b265acec5..cf23c0151721 100644 --- a/net/netlink/policy.c +++ b/net/netlink/policy.c @@ -63,44 +63,85 @@ static int add_policy(struct netlink_policy_dump_state **statep, return 0; } -static unsigned int get_policy_idx(struct netlink_policy_dump_state *state, - const struct nla_policy *policy, - unsigned int maxtype) +/** + * netlink_policy_dump_get_policy_idx - retrieve policy index + * @state: the policy dump state + * @policy: the policy to find + * @maxtype: the policy's maxattr + * + * Returns: the index of the given policy in the dump state + * + * Call this to find a policy index when you've added multiple and e.g. + * need to tell userspace which command has which policy (by index). + * + * Note: this will WARN and return 0 if the policy isn't found, which + * means it wasn't added in the first place, which would be an + * internal consistency bug. + */ +int netlink_policy_dump_get_policy_idx(struct netlink_policy_dump_state *state, + const struct nla_policy *policy, + unsigned int maxtype) { unsigned int i; + if (WARN_ON(!policy || !maxtype)) + return 0; + for (i = 0; i < state->n_alloc; i++) { if (state->policies[i].policy == policy && state->policies[i].maxtype == maxtype) return i; } - WARN_ON_ONCE(1); - return -1; + WARN_ON(1); + return 0; } -int netlink_policy_dump_start(const struct nla_policy *policy, - unsigned int maxtype, - struct netlink_policy_dump_state **statep) +static struct netlink_policy_dump_state *alloc_state(void) { struct netlink_policy_dump_state *state; + + state = kzalloc(struct_size(state, policies, INITIAL_POLICIES_ALLOC), + GFP_KERNEL); + if (!state) + return ERR_PTR(-ENOMEM); + state->n_alloc = INITIAL_POLICIES_ALLOC; + + return state; +} + +/** + * netlink_policy_dump_add_policy - add a policy to the dump + * @pstate: state to add to, may be reallocated, must be %NULL the first time + * @policy: the new policy to add to the dump + * @maxtype: the new policy's max attr type + * + * Returns: 0 on success, a negative error code otherwise. + * + * Call this to allocate a policy dump state, and to add policies to it. This + * should be called from the dump start() callback. + * + * Note: on failures, any previously allocated state is freed. + */ +int netlink_policy_dump_add_policy(struct netlink_policy_dump_state **pstate, + const struct nla_policy *policy, + unsigned int maxtype) +{ + struct netlink_policy_dump_state *state = *pstate; unsigned int policy_idx; int err; - if (*statep) - return 0; + if (!state) { + state = alloc_state(); + if (IS_ERR(state)) + return PTR_ERR(state); + } /* * walk the policies and nested ones first, and build * a linear list of them. */ - state = kzalloc(struct_size(state, policies, INITIAL_POLICIES_ALLOC), - GFP_KERNEL); - if (!state) - return -ENOMEM; - state->n_alloc = INITIAL_POLICIES_ALLOC; - err = add_policy(&state, policy, maxtype); if (err) return err; @@ -131,8 +172,7 @@ int netlink_policy_dump_start(const struct nla_policy *policy, } } - *statep = state; - + *pstate = state; return 0; } @@ -143,11 +183,26 @@ netlink_policy_dump_finished(struct netlink_policy_dump_state *state) !state->policies[state->policy_idx].policy; } +/** + * netlink_policy_dump_loop - dumping loop indicator + * @state: the policy dump state + * + * Returns: %true if the dump continues, %false otherwise + * + * Note: this frees the dump state when finishing + */ bool netlink_policy_dump_loop(struct netlink_policy_dump_state *state) { return !netlink_policy_dump_finished(state); } +/** + * netlink_policy_dump_write - write current policy dump attributes + * @skb: the message skb to write to + * @state: the policy dump state + * + * Returns: 0 on success, an error code otherwise + */ int netlink_policy_dump_write(struct sk_buff *skb, struct netlink_policy_dump_state *state) { @@ -185,8 +240,9 @@ send_attribute: type = NL_ATTR_TYPE_NESTED_ARRAY; if (pt->nested_policy && pt->len && (nla_put_u32(skb, NL_POLICY_TYPE_ATTR_POLICY_IDX, - get_policy_idx(state, pt->nested_policy, - pt->len)) || + netlink_policy_dump_get_policy_idx(state, + pt->nested_policy, + pt->len)) || nla_put_u32(skb, NL_POLICY_TYPE_ATTR_POLICY_MAXTYPE, pt->len))) goto nla_put_failure; @@ -309,6 +365,12 @@ nla_put_failure: return -ENOBUFS; } +/** + * netlink_policy_dump_free - free policy dump state + * @state: the policy dump state to free + * + * Call this from the done() method to ensure dump state is freed. + */ void netlink_policy_dump_free(struct netlink_policy_dump_state *state) { kfree(state); |