[PATCHv3 net-next 2/7] net: sched: cls_api: handle generic cls errors

Alexander Aring
2018-01-18T16:21:13Z

This patch adds extack support for generic cls handling. The extack
will be set deeper to each called function which is not part of netdev
core api.

Cc: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Aring <aring@mojatatu.com>
---
net/sched/cls_api.c | 52 +++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 41 insertions(+), 11 deletions(-)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index e500d11da9cd..76f40b3d89d3 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -122,7 +122,8 @@ static inline u32 tcf_auto_prio(struct tcf_proto *tp)
}

static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
- u32 prio, struct tcf_chain *chain)
+ u32 prio, struct tcf_chain *chain,
+ struct netlink_ext_ack *extack)
{
struct tcf_proto *tp;
int err;
@@ -148,6 +149,7 @@ static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
module_put(tp->ops->owner);
err = -EAGAIN;
} else {
+ NL_SET_ERR_MSG(extack, "TC classifier not found");
err = -ENOENT;
}
goto errout;
@@ -935,7 +937,8 @@ static int tfilter_notify(struct net *net, struct sk_buff *oskb,
static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
struct nlmsghdr *n, struct tcf_proto *tp,
struct tcf_block *block, struct Qdisc *q,
- u32 parent, void *fh, bool unicast, bool *last)
+ u32 parent, void *fh, bool unicast, bool *last,
+ struct netlink_ext_ack *extack)
{
struct sk_buff *skb;
u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
@@ -947,6 +950,7 @@ static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,

if (tcf_fill_node(net, skb, tp, block, q, parent, fh, portid,
n->nlmsg_seq, n->nlmsg_flags, RTM_DELTFILTER) <= 0) {
+ NL_SET_ERR_MSG(extack, "Failed to build del event notification");
kfree_skb(skb);
return -EINVAL;
}
@@ -960,8 +964,11 @@ static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
if (unicast)
return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);

- return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
- n->nlmsg_flags & NLM_F_ECHO);
+ err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
+ n->nlmsg_flags & NLM_F_ECHO);
+ if (err < 0)
+ NL_SET_ERR_MSG(extack, "Failed to send filter delete notification");
+ return err;
}

static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,
@@ -1021,8 +1028,10 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
if (prio == 0) {
switch (n->nlmsg_type) {
case RTM_DELTFILTER:
- if (protocol || t->tcm_handle || tca[TCA_KIND])
+ if (protocol || t->tcm_handle || tca[TCA_KIND]) {
+ NL_SET_ERR_MSG(extack, "Cannot flush filters with protocol, handle or kind set");
return -ENOENT;
+ }
break;
case RTM_NEWTFILTER:
/* If no priority is provided by the user,
@@ -1035,6 +1044,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
}
/* fall-through */
default:
+ NL_SET_ERR_MSG(extack, "Invalid filter command with priority of zero");
return -ENOENT;
}
}
@@ -1063,23 +1073,31 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
parent = q->handle;
} else {
q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
- if (!q)
+ if (!q) {
+ NL_SET_ERR_MSG(extack, "Parent Qdisc doesn't exists");
return -EINVAL;
+ }
}

/* Is it classful? */
cops = q->ops->cl_ops;
- if (!cops)
+ if (!cops) {
+ NL_SET_ERR_MSG(extack, "Qdisc not classful");
return -EINVAL;
+ }

- if (!cops->tcf_block)
+ if (!cops->tcf_block) {
+ NL_SET_ERR_MSG(extack, "Class doesn't support blocks");
return -EOPNOTSUPP;
+ }

/* Do we search for filter, attached to class? */
if (TC_H_MIN(parent)) {
cl = cops->find(q, parent);
- if (cl == 0)
+ if (cl == 0) {
+ NL_SET_ERR_MSG(extack, "Specified class doesn't exist");
return -ENOENT;
+ }
}

/* And the last stroke */
@@ -1097,12 +1115,14 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,

chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
if (chain_index > TC_ACT_EXT_VAL_MASK) {
+ NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");
err = -EINVAL;
goto errout;
}
chain = tcf_chain_get(block, chain_index,
n->nlmsg_type == RTM_NEWTFILTER);
if (!chain) {
+ NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");
err = n->nlmsg_type == RTM_NEWTFILTER ? -ENOMEM : -EINVAL;
goto errout;
}
@@ -1118,6 +1138,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
tp = tcf_chain_tp_find(chain, &chain_info, protocol,
prio, prio_allocate);
if (IS_ERR(tp)) {
+ NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
err = PTR_ERR(tp);
goto errout;
}
@@ -1126,12 +1147,14 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
/* Proto-tcf does not exist, create new one */

if (tca[TCA_KIND] == NULL || !protocol) {
+ NL_SET_ERR_MSG(extack, "Filter kind and protocol must be specified");
err = -EINVAL;
goto errout;
}

if (n->nlmsg_type != RTM_NEWTFILTER ||
!(n->nlmsg_flags & NLM_F_CREATE)) {
+ NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");
err = -ENOENT;
goto errout;
}
@@ -1140,13 +1163,14 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
prio = tcf_auto_prio(tcf_chain_tp_prev(&chain_info));

tp = tcf_proto_create(nla_data(tca[TCA_KIND]),
- protocol, prio, chain);
+ protocol, prio, chain, extack);
if (IS_ERR(tp)) {
err = PTR_ERR(tp);
goto errout;
}
tp_created = 1;
} else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
+ NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");
err = -EINVAL;
goto errout;
}
@@ -1165,6 +1189,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,

if (n->nlmsg_type != RTM_NEWTFILTER ||
!(n->nlmsg_flags & NLM_F_CREATE)) {
+ NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");
err = -ENOENT;
goto errout;
}
@@ -1176,13 +1201,15 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
if (n->nlmsg_flags & NLM_F_EXCL) {
if (tp_created)
tcf_proto_destroy(tp);
+ NL_SET_ERR_MSG(extack, "Filter already exists");
err = -EEXIST;
goto errout;
}
break;
case RTM_DELTFILTER:
err = tfilter_del_notify(net, skb, n, tp, block,
- q, parent, fh, false, &last);
+ q, parent, fh, false, &last,
+ extack);
if (err)
goto errout;
if (last) {
@@ -1193,8 +1220,11 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
case RTM_GETTFILTER:
err = tfilter_notify(net, skb, n, tp, block, q, parent,
fh, RTM_NEWTFILTER, true);
+ if (err < 0)
+ NL_SET_ERR_MSG(extack, "Failed to send filter notify message");
goto errout;
default:
+ NL_SET_ERR_MSG(extack, "Invalid netlink message type");
err = -EINVAL;
goto errout;
}
--
2.11.0