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Date: Fri, 31 Mar 2017 07:14:03 -0700
From: David Ahern <dsa@...ulusnetworks.com>
To: netdev@...r.kernel.org
Cc: roopa@...ulusnetworks.com, rshearma@...cade.com,
ebiederm@...ssion.com, David Ahern <dsa@...ulusnetworks.com>
Subject: [PATCH net-next v3 5/6] net: mpls: bump maximum number of labels
Allow users to push down more labels per MPLS route. With the previous
patches, no memory allocations are based on MAX_NEW_LABELS; the limit
is only used to keep userspace in check.
At this point MAX_NEW_LABELS is only used for mpls_route_config (copying
route data from userspace) and processing nexthops looking for the max
number of labels across the route spec.
Signed-off-by: David Ahern <dsa@...ulusnetworks.com>
---
v3
- initialize n_labels to 0 in case RTA_NEWDST is not defined; detected
by the kbuild test robot
v2
- increased MAX_NEW_LABELS to 30
- allocate mpls_route_config dynamically to reduce stack usage with
new label count
net/mpls/af_mpls.c | 103 +++++++++++++++++++++++++++++++++++-----------------
net/mpls/internal.h | 2 +-
2 files changed, 71 insertions(+), 34 deletions(-)
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index f84c52b6eafc..2458d7ed2ab5 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -24,7 +24,10 @@
#include <net/nexthop.h>
#include "internal.h"
-#define MAX_NEW_LABELS 2
+/* put a reasonable limit on the number of labels
+ * we will accept from userspace
+ */
+#define MAX_NEW_LABELS 30
/* max memory we will use for mpls_route */
#define MAX_MPLS_ROUTE_MEM 4096
@@ -698,9 +701,6 @@ static int mpls_nh_build_from_cfg(struct mpls_route_config *cfg,
return -ENOMEM;
err = -EINVAL;
- /* Ensure only a supported number of labels are present */
- if (cfg->rc_output_labels > MAX_NEW_LABELS)
- goto errout;
nh->nh_labels = cfg->rc_output_labels;
for (i = 0; i < nh->nh_labels; i++)
@@ -725,7 +725,7 @@ static int mpls_nh_build_from_cfg(struct mpls_route_config *cfg,
static int mpls_nh_build(struct net *net, struct mpls_route *rt,
struct mpls_nh *nh, int oif, struct nlattr *via,
- struct nlattr *newdst)
+ struct nlattr *newdst, u8 max_labels)
{
int err = -ENOMEM;
@@ -733,7 +733,7 @@ static int mpls_nh_build(struct net *net, struct mpls_route *rt,
goto errout;
if (newdst) {
- err = nla_get_labels(newdst, MAX_NEW_LABELS,
+ err = nla_get_labels(newdst, max_labels,
&nh->nh_labels, nh->nh_label);
if (err)
goto errout;
@@ -759,21 +759,19 @@ static int mpls_nh_build(struct net *net, struct mpls_route *rt,
}
static u8 mpls_count_nexthops(struct rtnexthop *rtnh, int len,
- u8 cfg_via_alen, u8 *max_via_alen)
+ u8 cfg_via_alen, u8 *max_via_alen,
+ u8 *max_labels)
{
int remaining = len;
u8 nhs = 0;
- if (!rtnh) {
- *max_via_alen = cfg_via_alen;
- return 1;
- }
-
*max_via_alen = 0;
+ *max_labels = 0;
while (rtnh_ok(rtnh, remaining)) {
struct nlattr *nla, *attrs = rtnh_attrs(rtnh);
int attrlen;
+ u8 n_labels = 0;
attrlen = rtnh_attrlen(rtnh);
nla = nla_find(attrs, attrlen, RTA_VIA);
@@ -787,6 +785,13 @@ static u8 mpls_count_nexthops(struct rtnexthop *rtnh, int len,
via_alen);
}
+ nla = nla_find(attrs, attrlen, RTA_NEWDST);
+ if (nla &&
+ nla_get_labels(nla, MAX_NEW_LABELS, &n_labels, NULL) != 0)
+ return 0;
+
+ *max_labels = max_t(u8, *max_labels, n_labels);
+
/* number of nexthops is tracked by a u8.
* Check for overflow.
*/
@@ -802,7 +807,7 @@ static u8 mpls_count_nexthops(struct rtnexthop *rtnh, int len,
}
static int mpls_nh_build_multi(struct mpls_route_config *cfg,
- struct mpls_route *rt)
+ struct mpls_route *rt, u8 max_labels)
{
struct rtnexthop *rtnh = cfg->rc_mp;
struct nlattr *nla_via, *nla_newdst;
@@ -835,7 +840,8 @@ static int mpls_nh_build_multi(struct mpls_route_config *cfg,
}
err = mpls_nh_build(cfg->rc_nlinfo.nl_net, rt, nh,
- rtnh->rtnh_ifindex, nla_via, nla_newdst);
+ rtnh->rtnh_ifindex, nla_via, nla_newdst,
+ max_labels);
if (err)
goto errout;
@@ -862,6 +868,7 @@ static int mpls_route_add(struct mpls_route_config *cfg)
int err = -EINVAL;
u8 max_via_alen;
unsigned index;
+ u8 max_labels;
u8 nhs;
index = cfg->rc_label;
@@ -900,13 +907,21 @@ static int mpls_route_add(struct mpls_route_config *cfg)
goto errout;
err = -EINVAL;
- nhs = mpls_count_nexthops(cfg->rc_mp, cfg->rc_mp_len,
- cfg->rc_via_alen, &max_via_alen);
+ if (cfg->rc_mp) {
+ nhs = mpls_count_nexthops(cfg->rc_mp, cfg->rc_mp_len,
+ cfg->rc_via_alen, &max_via_alen,
+ &max_labels);
+ } else {
+ max_via_alen = cfg->rc_via_alen;
+ max_labels = cfg->rc_output_labels;
+ nhs = 1;
+ }
+
if (nhs == 0)
goto errout;
err = -ENOMEM;
- rt = mpls_rt_alloc(nhs, max_via_alen, MAX_NEW_LABELS);
+ rt = mpls_rt_alloc(nhs, max_via_alen, max_labels);
if (IS_ERR(rt)) {
err = PTR_ERR(rt);
goto errout;
@@ -917,7 +932,7 @@ static int mpls_route_add(struct mpls_route_config *cfg)
rt->rt_ttl_propagate = cfg->rc_ttl_propagate;
if (cfg->rc_mp)
- err = mpls_nh_build_multi(cfg, rt);
+ err = mpls_nh_build_multi(cfg, rt, max_labels);
else
err = mpls_nh_build_from_cfg(cfg, rt);
if (err)
@@ -1531,16 +1546,18 @@ int nla_put_labels(struct sk_buff *skb, int attrtype,
EXPORT_SYMBOL_GPL(nla_put_labels);
int nla_get_labels(const struct nlattr *nla,
- u32 max_labels, u8 *labels, u32 label[])
+ u8 max_labels, u8 *labels, u32 label[])
{
unsigned len = nla_len(nla);
- unsigned nla_labels;
struct mpls_shim_hdr *nla_label;
+ u8 nla_labels;
bool bos;
int i;
- /* len needs to be an even multiple of 4 (the label size) */
- if (len & 3)
+ /* len needs to be an even multiple of 4 (the label size). Number
+ * of labels is a u8 so check for overflow.
+ */
+ if (len & 3 || len / 4 > 255)
return -EINVAL;
/* Limit the number of new labels allowed */
@@ -1548,6 +1565,10 @@ int nla_get_labels(const struct nlattr *nla,
if (nla_labels > max_labels)
return -EINVAL;
+ /* when label == NULL, caller wants number of labels */
+ if (!label)
+ goto out;
+
nla_label = nla_data(nla);
bos = true;
for (i = nla_labels - 1; i >= 0; i--, bos = false) {
@@ -1571,6 +1592,7 @@ int nla_get_labels(const struct nlattr *nla,
label[i] = dec.label;
}
+out:
*labels = nla_labels;
return 0;
}
@@ -1632,7 +1654,6 @@ static int rtm_to_route_config(struct sk_buff *skb, struct nlmsghdr *nlh,
err = -EINVAL;
rtm = nlmsg_data(nlh);
- memset(cfg, 0, sizeof(*cfg));
if (rtm->rtm_family != AF_MPLS)
goto errout;
@@ -1731,27 +1752,43 @@ static int rtm_to_route_config(struct sk_buff *skb, struct nlmsghdr *nlh,
static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh)
{
- struct mpls_route_config cfg;
+ struct mpls_route_config *cfg;
int err;
- err = rtm_to_route_config(skb, nlh, &cfg);
+ cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
+ if (!cfg)
+ return -ENOMEM;
+
+ err = rtm_to_route_config(skb, nlh, cfg);
if (err < 0)
- return err;
+ goto out;
- return mpls_route_del(&cfg);
+ err = mpls_route_del(cfg);
+out:
+ kfree(cfg);
+
+ return err;
}
static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh)
{
- struct mpls_route_config cfg;
+ struct mpls_route_config *cfg;
int err;
- err = rtm_to_route_config(skb, nlh, &cfg);
+ cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
+ if (!cfg)
+ return -ENOMEM;
+
+ err = rtm_to_route_config(skb, nlh, cfg);
if (err < 0)
- return err;
+ goto out;
- return mpls_route_add(&cfg);
+ err = mpls_route_add(cfg);
+out:
+ kfree(cfg);
+
+ return err;
}
static int mpls_dump_route(struct sk_buff *skb, u32 portid, u32 seq, int event,
@@ -1980,7 +2017,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
/* In case the predefined labels need to be populated */
if (limit > MPLS_LABEL_IPV4NULL) {
struct net_device *lo = net->loopback_dev;
- rt0 = mpls_rt_alloc(1, lo->addr_len, MAX_NEW_LABELS);
+ rt0 = mpls_rt_alloc(1, lo->addr_len, 0);
if (IS_ERR(rt0))
goto nort0;
RCU_INIT_POINTER(rt0->rt_nh->nh_dev, lo);
@@ -1994,7 +2031,7 @@ static int resize_platform_label_table(struct net *net, size_t limit)
}
if (limit > MPLS_LABEL_IPV6NULL) {
struct net_device *lo = net->loopback_dev;
- rt2 = mpls_rt_alloc(1, lo->addr_len, MAX_NEW_LABELS);
+ rt2 = mpls_rt_alloc(1, lo->addr_len, 0);
if (IS_ERR(rt2))
goto nort2;
RCU_INIT_POINTER(rt2->rt_nh->nh_dev, lo);
diff --git a/net/mpls/internal.h b/net/mpls/internal.h
index cc324c022049..c5d2f5bc37ec 100644
--- a/net/mpls/internal.h
+++ b/net/mpls/internal.h
@@ -197,7 +197,7 @@ static inline struct mpls_dev *mpls_dev_get(const struct net_device *dev)
int nla_put_labels(struct sk_buff *skb, int attrtype, u8 labels,
const u32 label[]);
-int nla_get_labels(const struct nlattr *nla, u32 max_labels, u8 *labels,
+int nla_get_labels(const struct nlattr *nla, u8 max_labels, u8 *labels,
u32 label[]);
int nla_get_via(const struct nlattr *nla, u8 *via_alen, u8 *via_table,
u8 via[]);
--
2.1.4
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