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linux/net/ipv6/seg6.c
Tom Herbert 97a6ec4ac0 rhashtable: Change rhashtable_walk_start to return void 
Most callers of rhashtable_walk_start don't care about a resize event
which is indicated by a return value of -EAGAIN. So calls to
rhashtable_walk_start are wrapped wih code to ignore -EAGAIN. Something
like this is common:

       ret = rhashtable_walk_start(rhiter);
       if (ret && ret != -EAGAIN)
               goto out;

Since zero and -EAGAIN are the only possible return values from the
function this check is pointless. The condition never evaluates to true.

This patch changes rhashtable_walk_start to return void. This simplifies
code for the callers that ignore -EAGAIN. For the few cases where the
caller cares about the resize event, particularly where the table can be
walked in mulitple parts for netlink or seq file dump, the function
rhashtable_walk_start_check has been added that returns -EAGAIN on a
resize event.

Signed-off-by: Tom Herbert <tom@quantonium.net>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-11 09:58:38 -05:00

500 lines
9.8 KiB
C
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/*
* SR-IPv6 implementation
*
* Author:
* David Lebrun <david.lebrun@uclouvain.be>
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/slab.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/seg6.h>
#include <net/genetlink.h>
#include <linux/seg6.h>
#include <linux/seg6_genl.h>
#ifdef CONFIG_IPV6_SEG6_HMAC
#include <net/seg6_hmac.h>
#endif
bool seg6_validate_srh(struct ipv6_sr_hdr *srh, int len)
{
int trailing;
unsigned int tlv_offset;
if (srh->type != IPV6_SRCRT_TYPE_4)
return false;
if (((srh->hdrlen + 1) << 3) != len)
return false;
if (srh->segments_left > srh->first_segment)
return false;
tlv_offset = sizeof(*srh) + ((srh->first_segment + 1) << 4);
trailing = len - tlv_offset;
if (trailing < 0)
return false;
while (trailing) {
struct sr6_tlv *tlv;
unsigned int tlv_len;
if (trailing < sizeof(*tlv))
return false;
tlv = (struct sr6_tlv *)((unsigned char *)srh + tlv_offset);
tlv_len = sizeof(*tlv) + tlv->len;
trailing -= tlv_len;
if (trailing < 0)
return false;
tlv_offset += tlv_len;
}
return true;
}
static struct genl_family seg6_genl_family;
static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {
[SEG6_ATTR_DST] = { .type = NLA_BINARY,
.len = sizeof(struct in6_addr) },
[SEG6_ATTR_DSTLEN] = { .type = NLA_S32, },
[SEG6_ATTR_HMACKEYID] = { .type = NLA_U32, },
[SEG6_ATTR_SECRET] = { .type = NLA_BINARY, },
[SEG6_ATTR_SECRETLEN] = { .type = NLA_U8, },
[SEG6_ATTR_ALGID] = { .type = NLA_U8, },
[SEG6_ATTR_HMACINFO] = { .type = NLA_NESTED, },
};
#ifdef CONFIG_IPV6_SEG6_HMAC
static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = genl_info_net(info);
struct seg6_pernet_data *sdata;
struct seg6_hmac_info *hinfo;
u32 hmackeyid;
char *secret;
int err = 0;
u8 algid;
u8 slen;
sdata = seg6_pernet(net);
if (!info->attrs[SEG6_ATTR_HMACKEYID] ||
!info->attrs[SEG6_ATTR_SECRETLEN] ||
!info->attrs[SEG6_ATTR_ALGID])
return -EINVAL;
hmackeyid = nla_get_u32(info->attrs[SEG6_ATTR_HMACKEYID]);
slen = nla_get_u8(info->attrs[SEG6_ATTR_SECRETLEN]);
algid = nla_get_u8(info->attrs[SEG6_ATTR_ALGID]);
if (hmackeyid == 0)
return -EINVAL;
if (slen > SEG6_HMAC_SECRET_LEN)
return -EINVAL;
mutex_lock(&sdata->lock);
hinfo = seg6_hmac_info_lookup(net, hmackeyid);
if (!slen) {
if (!hinfo)
err = -ENOENT;
err = seg6_hmac_info_del(net, hmackeyid);
goto out_unlock;
}
if (!info->attrs[SEG6_ATTR_SECRET]) {
err = -EINVAL;
goto out_unlock;
}
if (hinfo) {
err = seg6_hmac_info_del(net, hmackeyid);
if (err)
goto out_unlock;
}
secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
if (!hinfo) {
err = -ENOMEM;
goto out_unlock;
}
memcpy(hinfo->secret, secret, slen);
hinfo->slen = slen;
hinfo->alg_id = algid;
hinfo->hmackeyid = hmackeyid;
err = seg6_hmac_info_add(net, hmackeyid, hinfo);
if (err)
kfree(hinfo);
out_unlock:
mutex_unlock(&sdata->lock);
return err;
}
#else
static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
{
return -ENOTSUPP;
}
#endif
static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = genl_info_net(info);
struct in6_addr *val, *t_old, *t_new;
struct seg6_pernet_data *sdata;
sdata = seg6_pernet(net);
if (!info->attrs[SEG6_ATTR_DST])
return -EINVAL;
val = nla_data(info->attrs[SEG6_ATTR_DST]);
t_new = kmemdup(val, sizeof(*val), GFP_KERNEL);
if (!t_new)
return -ENOMEM;
mutex_lock(&sdata->lock);
t_old = sdata->tun_src;
rcu_assign_pointer(sdata->tun_src, t_new);
mutex_unlock(&sdata->lock);
synchronize_net();
kfree(t_old);
return 0;
}
static int seg6_genl_get_tunsrc(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = genl_info_net(info);
struct in6_addr *tun_src;
struct sk_buff *msg;
void *hdr;
msg = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
if (!msg)
return -ENOMEM;
hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
&seg6_genl_family, 0, SEG6_CMD_GET_TUNSRC);
if (!hdr)
goto free_msg;
rcu_read_lock();
tun_src = rcu_dereference(seg6_pernet(net)->tun_src);
if (nla_put(msg, SEG6_ATTR_DST, sizeof(struct in6_addr), tun_src))
goto nla_put_failure;
rcu_read_unlock();
genlmsg_end(msg, hdr);
genlmsg_reply(msg, info);
return 0;
nla_put_failure:
rcu_read_unlock();
genlmsg_cancel(msg, hdr);
free_msg:
nlmsg_free(msg);
return -ENOMEM;
}
#ifdef CONFIG_IPV6_SEG6_HMAC
static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
struct sk_buff *msg)
{
if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
return -1;
return 0;
}
static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
u32 portid, u32 seq, u32 flags,
struct sk_buff *skb, u8 cmd)
{
void *hdr;
hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
if (!hdr)
return -ENOMEM;
if (__seg6_hmac_fill_info(hinfo, skb) < 0)
goto nla_put_failure;
genlmsg_end(skb, hdr);
return 0;
nla_put_failure:
genlmsg_cancel(skb, hdr);
return -EMSGSIZE;
}
static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
{
struct net *net = sock_net(cb->skb->sk);
struct seg6_pernet_data *sdata;
struct rhashtable_iter *iter;
sdata = seg6_pernet(net);
iter = (struct rhashtable_iter *)cb->args[0];
if (!iter) {
iter = kmalloc(sizeof(*iter), GFP_KERNEL);
if (!iter)
return -ENOMEM;
cb->args[0] = (long)iter;
}
rhashtable_walk_enter(&sdata->hmac_infos, iter);
return 0;
}
static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
{
struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
rhashtable_walk_exit(iter);
kfree(iter);
return 0;
}
static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
{
struct rhashtable_iter *iter = (struct rhashtable_iter *)cb->args[0];
struct seg6_hmac_info *hinfo;
int ret;
rhashtable_walk_start(iter);
for (;;) {
hinfo = rhashtable_walk_next(iter);
if (IS_ERR(hinfo)) {
if (PTR_ERR(hinfo) == -EAGAIN)
continue;
ret = PTR_ERR(hinfo);
goto done;
} else if (!hinfo) {
break;
}
ret = __seg6_genl_dumphmac_element(hinfo,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq,
NLM_F_MULTI,
skb, SEG6_CMD_DUMPHMAC);
if (ret)
goto done;
}
ret = skb->len;
done:
rhashtable_walk_stop(iter);
return ret;
}
#else
static int seg6_genl_dumphmac_start(struct netlink_callback *cb)
{
return 0;
}
static int seg6_genl_dumphmac_done(struct netlink_callback *cb)
{
return 0;
}
static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
{
return -ENOTSUPP;
}
#endif
static int __net_init seg6_net_init(struct net *net)
{
struct seg6_pernet_data *sdata;
sdata = kzalloc(sizeof(*sdata), GFP_KERNEL);
if (!sdata)
return -ENOMEM;
mutex_init(&sdata->lock);
sdata->tun_src = kzalloc(sizeof(*sdata->tun_src), GFP_KERNEL);
if (!sdata->tun_src) {
kfree(sdata);
return -ENOMEM;
}
net->ipv6.seg6_data = sdata;
#ifdef CONFIG_IPV6_SEG6_HMAC
seg6_hmac_net_init(net);
#endif
return 0;
}
static void __net_exit seg6_net_exit(struct net *net)
{
struct seg6_pernet_data *sdata = seg6_pernet(net);
#ifdef CONFIG_IPV6_SEG6_HMAC
seg6_hmac_net_exit(net);
#endif
kfree(sdata->tun_src);
kfree(sdata);
}
static struct pernet_operations ip6_segments_ops = {
.init = seg6_net_init,
.exit = seg6_net_exit,
};
static const struct genl_ops seg6_genl_ops[] = {
{
.cmd = SEG6_CMD_SETHMAC,
.doit = seg6_genl_sethmac,
.policy = seg6_genl_policy,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = SEG6_CMD_DUMPHMAC,
.start = seg6_genl_dumphmac_start,
.dumpit = seg6_genl_dumphmac,
.done = seg6_genl_dumphmac_done,
.policy = seg6_genl_policy,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = SEG6_CMD_SET_TUNSRC,
.doit = seg6_genl_set_tunsrc,
.policy = seg6_genl_policy,
.flags = GENL_ADMIN_PERM,
},
{
.cmd = SEG6_CMD_GET_TUNSRC,
.doit = seg6_genl_get_tunsrc,
.policy = seg6_genl_policy,
.flags = GENL_ADMIN_PERM,
},
};
static struct genl_family seg6_genl_family __ro_after_init = {
.hdrsize = 0,
.name = SEG6_GENL_NAME,
.version = SEG6_GENL_VERSION,
.maxattr = SEG6_ATTR_MAX,
.netnsok = true,
.parallel_ops = true,
.ops = seg6_genl_ops,
.n_ops = ARRAY_SIZE(seg6_genl_ops),
.module = THIS_MODULE,
};
int __init seg6_init(void)
{
int err = -ENOMEM;
err = genl_register_family(&seg6_genl_family);
if (err)
goto out;
err = register_pernet_subsys(&ip6_segments_ops);
if (err)
goto out_unregister_genl;
#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
err = seg6_iptunnel_init();
if (err)
goto out_unregister_pernet;
err = seg6_local_init();
if (err)
goto out_unregister_pernet;
#endif
#ifdef CONFIG_IPV6_SEG6_HMAC
err = seg6_hmac_init();
if (err)
goto out_unregister_iptun;
#endif
pr_info("Segment Routing with IPv6\n");
out:
return err;
#ifdef CONFIG_IPV6_SEG6_HMAC
out_unregister_iptun:
#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
seg6_local_exit();
seg6_iptunnel_exit();
#endif
#endif
#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
out_unregister_pernet:
unregister_pernet_subsys(&ip6_segments_ops);
#endif
out_unregister_genl:
genl_unregister_family(&seg6_genl_family);
goto out;
}
void seg6_exit(void)
{
#ifdef CONFIG_IPV6_SEG6_HMAC
seg6_hmac_exit();
#endif
#ifdef CONFIG_IPV6_SEG6_LWTUNNEL
seg6_iptunnel_exit();
#endif
unregister_pernet_subsys(&ip6_segments_ops);
genl_unregister_family(&seg6_genl_family);
}
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