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decnet: Parse netlink attributes on our own
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decnet is the only subsystem left that is relying on the global
netlink attribute buffer rta_buf. It's horrible design and we
want to get rid of it.

This converts all of decnet to do implicit attribute parsing. It
also gets rid of the error prone struct dn_kern_rta.

Yes, the fib_magic() stuff is not pretty.

It's compiled tested but I need someone with appropriate hardware
to test the patch since I don't have access to it.

Cc: linux-decnet-user@lists.sourceforge.net
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Thomas Graf authored and David S. Miller committed Mar 22, 2013
1 parent 9b924db commit 58d7d8f
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Showing 4 changed files with 160 additions and 148 deletions.
28 changes: 6 additions & 22 deletions include/net/dn_fib.h
View file
Original file line number Diff line number Diff line change
@@ -1,24 +1,9 @@
#ifndef _NET_DN_FIB_H
#define _NET_DN_FIB_H

/* WARNING: The ordering of these elements must match ordering
* of RTA_* rtnetlink attribute numbers.
*/
struct dn_kern_rta {
void *rta_dst;
void *rta_src;
int *rta_iif;
int *rta_oif;
void *rta_gw;
u32 *rta_priority;
void *rta_prefsrc;
struct rtattr *rta_mx;
struct rtattr *rta_mp;
unsigned char *rta_protoinfo;
u32 *rta_flow;
struct rta_cacheinfo *rta_ci;
struct rta_session *rta_sess;
};
#include <linux/netlink.h>

extern const struct nla_policy rtm_dn_policy[];

struct dn_fib_res {
struct fib_rule *r;
Expand Down Expand Up @@ -93,10 +78,10 @@ struct dn_fib_table {
u32 n;

int (*insert)(struct dn_fib_table *t, struct rtmsg *r,
struct dn_kern_rta *rta, struct nlmsghdr *n,
struct nlattr *attrs[], struct nlmsghdr *n,
struct netlink_skb_parms *req);
int (*delete)(struct dn_fib_table *t, struct rtmsg *r,
struct dn_kern_rta *rta, struct nlmsghdr *n,
struct nlattr *attrs[], struct nlmsghdr *n,
struct netlink_skb_parms *req);
int (*lookup)(struct dn_fib_table *t, const struct flowidn *fld,
struct dn_fib_res *res);
Expand All @@ -116,13 +101,12 @@ extern void dn_fib_cleanup(void);
extern int dn_fib_ioctl(struct socket *sock, unsigned int cmd,
unsigned long arg);
extern struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r,
struct dn_kern_rta *rta,
struct nlattr *attrs[],
const struct nlmsghdr *nlh, int *errp);
extern int dn_fib_semantic_match(int type, struct dn_fib_info *fi,
const struct flowidn *fld,
struct dn_fib_res *res);
extern void dn_fib_release_info(struct dn_fib_info *fi);
extern __le16 dn_fib_get_attr16(struct rtattr *attr, int attrlen, int type);
extern void dn_fib_flush(void);
extern void dn_fib_select_multipath(const struct flowidn *fld,
struct dn_fib_res *res);
Expand Down
211 changes: 115 additions & 96 deletions net/decnet/dn_fib.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -145,22 +145,10 @@ static inline struct dn_fib_info *dn_fib_find_info(const struct dn_fib_info *nfi
return NULL;
}

__le16 dn_fib_get_attr16(struct rtattr *attr, int attrlen, int type)
static int dn_fib_count_nhs(const struct nlattr *attr)
{
while(RTA_OK(attr,attrlen)) {
if (attr->rta_type == type)
return *(__le16*)RTA_DATA(attr);
attr = RTA_NEXT(attr, attrlen);
}

return 0;
}

static int dn_fib_count_nhs(struct rtattr *rta)
{
int nhs = 0;
struct rtnexthop *nhp = RTA_DATA(rta);
int nhlen = RTA_PAYLOAD(rta);
struct rtnexthop *nhp = nla_data(attr);
int nhs = 0, nhlen = nla_len(attr);

while(nhlen >= (int)sizeof(struct rtnexthop)) {
if ((nhlen -= nhp->rtnh_len) < 0)
Expand All @@ -172,10 +160,11 @@ static int dn_fib_count_nhs(struct rtattr *rta)
return nhs;
}

static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct rtattr *rta, const struct rtmsg *r)
static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct nlattr *attr,
const struct rtmsg *r)
{
struct rtnexthop *nhp = RTA_DATA(rta);
int nhlen = RTA_PAYLOAD(rta);
struct rtnexthop *nhp = nla_data(attr);
int nhlen = nla_len(attr);

change_nexthops(fi) {
int attrlen = nhlen - sizeof(struct rtnexthop);
Expand All @@ -187,7 +176,10 @@ static int dn_fib_get_nhs(struct dn_fib_info *fi, const struct rtattr *rta, cons
nh->nh_weight = nhp->rtnh_hops + 1;

if (attrlen) {
nh->nh_gw = dn_fib_get_attr16(RTNH_DATA(nhp), attrlen, RTA_GATEWAY);
struct nlattr *gw_attr;

gw_attr = nla_find((struct nlattr *) (nhp + 1), attrlen, RTA_GATEWAY);
nh->nh_gw = gw_attr ? nla_get_le16(gw_attr) : 0;
}
nhp = RTNH_NEXT(nhp);
} endfor_nexthops(fi);
Expand Down Expand Up @@ -268,7 +260,8 @@ static int dn_fib_check_nh(const struct rtmsg *r, struct dn_fib_info *fi, struct
}


struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta *rta, const struct nlmsghdr *nlh, int *errp)
struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct nlattr *attrs[],
const struct nlmsghdr *nlh, int *errp)
{
int err;
struct dn_fib_info *fi = NULL;
Expand All @@ -281,11 +274,9 @@ struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta
if (dn_fib_props[r->rtm_type].scope > r->rtm_scope)
goto err_inval;

if (rta->rta_mp) {
nhs = dn_fib_count_nhs(rta->rta_mp);
if (nhs == 0)
goto err_inval;
}
if (attrs[RTA_MULTIPATH] &&
(nhs = dn_fib_count_nhs(attrs[RTA_MULTIPATH])) == 0)
goto err_inval;

fi = kzalloc(sizeof(*fi)+nhs*sizeof(struct dn_fib_nh), GFP_KERNEL);
err = -ENOBUFS;
Expand All @@ -295,53 +286,65 @@ struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta
fi->fib_protocol = r->rtm_protocol;
fi->fib_nhs = nhs;
fi->fib_flags = r->rtm_flags;
if (rta->rta_priority)
fi->fib_priority = *rta->rta_priority;
if (rta->rta_mx) {
int attrlen = RTA_PAYLOAD(rta->rta_mx);
struct rtattr *attr = RTA_DATA(rta->rta_mx);

while(RTA_OK(attr, attrlen)) {
unsigned int flavour = attr->rta_type;
if (attrs[RTA_PRIORITY])
fi->fib_priority = nla_get_u32(attrs[RTA_PRIORITY]);

if (attrs[RTA_METRICS]) {
struct nlattr *attr;
int rem;

if (flavour) {
if (flavour > RTAX_MAX)
nla_for_each_nested(attr, attrs[RTA_METRICS], rem) {
int type = nla_type(attr);

if (type) {
if (type > RTAX_MAX || nla_len(attr) < 4)
goto err_inval;
fi->fib_metrics[flavour-1] = *(unsigned int *)RTA_DATA(attr);

fi->fib_metrics[type-1] = nla_get_u32(attr);
}
attr = RTA_NEXT(attr, attrlen);
}
}
if (rta->rta_prefsrc)
memcpy(&fi->fib_prefsrc, rta->rta_prefsrc, 2);

if (rta->rta_mp) {
if ((err = dn_fib_get_nhs(fi, rta->rta_mp, r)) != 0)
if (attrs[RTA_PREFSRC])
fi->fib_prefsrc = nla_get_le16(attrs[RTA_PREFSRC]);

if (attrs[RTA_MULTIPATH]) {
if ((err = dn_fib_get_nhs(fi, attrs[RTA_MULTIPATH], r)) != 0)
goto failure;
if (rta->rta_oif && fi->fib_nh->nh_oif != *rta->rta_oif)

if (attrs[RTA_OIF] &&
fi->fib_nh->nh_oif != nla_get_u32(attrs[RTA_OIF]))
goto err_inval;
if (rta->rta_gw && memcmp(&fi->fib_nh->nh_gw, rta->rta_gw, 2))

if (attrs[RTA_GATEWAY] &&
fi->fib_nh->nh_gw != nla_get_le16(attrs[RTA_GATEWAY]))
goto err_inval;
} else {
struct dn_fib_nh *nh = fi->fib_nh;
if (rta->rta_oif)
nh->nh_oif = *rta->rta_oif;
if (rta->rta_gw)
memcpy(&nh->nh_gw, rta->rta_gw, 2);

if (attrs[RTA_OIF])
nh->nh_oif = nla_get_u32(attrs[RTA_OIF]);

if (attrs[RTA_GATEWAY])
nh->nh_gw = nla_get_le16(attrs[RTA_GATEWAY]);

nh->nh_flags = r->rtm_flags;
nh->nh_weight = 1;
}

if (r->rtm_type == RTN_NAT) {
if (rta->rta_gw == NULL || nhs != 1 || rta->rta_oif)
if (!attrs[RTA_GATEWAY] || nhs != 1 || attrs[RTA_OIF])
goto err_inval;
memcpy(&fi->fib_nh->nh_gw, rta->rta_gw, 2);

fi->fib_nh->nh_gw = nla_get_le16(attrs[RTA_GATEWAY]);
goto link_it;
}

if (dn_fib_props[r->rtm_type].error) {
if (rta->rta_gw || rta->rta_oif || rta->rta_mp)
if (attrs[RTA_GATEWAY] || attrs[RTA_OIF] || attrs[RTA_MULTIPATH])
goto err_inval;

goto link_it;
}

Expand All @@ -367,8 +370,8 @@ struct dn_fib_info *dn_fib_create_info(const struct rtmsg *r, struct dn_kern_rta
}

if (fi->fib_prefsrc) {
if (r->rtm_type != RTN_LOCAL || rta->rta_dst == NULL ||
memcmp(&fi->fib_prefsrc, rta->rta_dst, 2))
if (r->rtm_type != RTN_LOCAL || !attrs[RTA_DST] ||
fi->fib_prefsrc != nla_get_le16(attrs[RTA_DST]))
if (dnet_addr_type(fi->fib_prefsrc) != RTN_LOCAL)
goto err_inval;
}
Expand Down Expand Up @@ -486,29 +489,24 @@ void dn_fib_select_multipath(const struct flowidn *fld, struct dn_fib_res *res)
spin_unlock_bh(&dn_fib_multipath_lock);
}

const struct nla_policy rtm_dn_policy[RTA_MAX + 1] = {
[RTA_DST] = { .type = NLA_U16 },
[RTA_SRC] = { .type = NLA_U16 },
[RTA_IIF] = { .type = NLA_U32 },
[RTA_OIF] = { .type = NLA_U32 },
[RTA_GATEWAY] = { .type = NLA_U16 },
[RTA_PRIORITY] = { .type = NLA_U32 },
[RTA_PREFSRC] = { .type = NLA_U16 },
[RTA_METRICS] = { .type = NLA_NESTED },
[RTA_MULTIPATH] = { .type = NLA_NESTED },
[RTA_TABLE] = { .type = NLA_U32 },
[RTA_MARK] = { .type = NLA_U32 },
};

static int dn_fib_check_attr(struct rtmsg *r, struct rtattr **rta)
{
int i;

for(i = 1; i <= RTA_MAX; i++) {
struct rtattr *attr = rta[i-1];
if (attr) {
if (RTA_PAYLOAD(attr) < 4 && RTA_PAYLOAD(attr) != 2)
return -EINVAL;
if (i != RTA_MULTIPATH && i != RTA_METRICS &&
i != RTA_TABLE)
rta[i-1] = (struct rtattr *)RTA_DATA(attr);
}
}

return 0;
}

static inline u32 rtm_get_table(struct rtattr **rta, u8 table)
static inline u32 rtm_get_table(struct nlattr *attrs[], u8 table)
{
if (rta[RTA_TABLE - 1])
table = nla_get_u32((struct nlattr *) rta[RTA_TABLE - 1]);
if (attrs[RTA_TABLE])
table = nla_get_u32(attrs[RTA_TABLE]);

return table;
}
Expand All @@ -517,46 +515,50 @@ static int dn_fib_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *
{
struct net *net = sock_net(skb->sk);
struct dn_fib_table *tb;
struct rtattr **rta = arg;
struct rtmsg *r = NLMSG_DATA(nlh);
struct rtmsg *r = nlmsg_data(nlh);
struct nlattr *attrs[RTA_MAX+1];
int err;

if (!capable(CAP_NET_ADMIN))
return -EPERM;

if (!net_eq(net, &init_net))
return -EINVAL;

if (dn_fib_check_attr(r, rta))
return -EINVAL;
err = nlmsg_parse(nlh, sizeof(*r), attrs, RTA_MAX, rtm_dn_policy);
if (err < 0)
return err;

tb = dn_fib_get_table(rtm_get_table(rta, r->rtm_table), 0);
if (tb)
return tb->delete(tb, r, (struct dn_kern_rta *)rta, nlh, &NETLINK_CB(skb));
tb = dn_fib_get_table(rtm_get_table(attrs, r->rtm_table), 0);
if (!tb)
return -ESRCH;

return -ESRCH;
return tb->delete(tb, r, attrs, nlh, &NETLINK_CB(skb));
}

static int dn_fib_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
{
struct net *net = sock_net(skb->sk);
struct dn_fib_table *tb;
struct rtattr **rta = arg;
struct rtmsg *r = NLMSG_DATA(nlh);
struct rtmsg *r = nlmsg_data(nlh);
struct nlattr *attrs[RTA_MAX+1];
int err;

if (!capable(CAP_NET_ADMIN))
return -EPERM;

if (!net_eq(net, &init_net))
return -EINVAL;

if (dn_fib_check_attr(r, rta))
return -EINVAL;
err = nlmsg_parse(nlh, sizeof(*r), attrs, RTA_MAX, rtm_dn_policy);
if (err < 0)
return err;

tb = dn_fib_get_table(rtm_get_table(rta, r->rtm_table), 1);
if (tb)
return tb->insert(tb, r, (struct dn_kern_rta *)rta, nlh, &NETLINK_CB(skb));
tb = dn_fib_get_table(rtm_get_table(attrs, r->rtm_table), 1);
if (!tb)
return -ENOBUFS;

return -ENOBUFS;
return tb->insert(tb, r, attrs, nlh, &NETLINK_CB(skb));
}

static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifaddr *ifa)
Expand All @@ -566,10 +568,31 @@ static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifad
struct nlmsghdr nlh;
struct rtmsg rtm;
} req;
struct dn_kern_rta rta;
struct {
struct nlattr hdr;
__le16 dst;
} dst_attr = {
.dst = dst,
};
struct {
struct nlattr hdr;
__le16 prefsrc;
} prefsrc_attr = {
.prefsrc = ifa->ifa_local,
};
struct {
struct nlattr hdr;
u32 oif;
} oif_attr = {
.oif = ifa->ifa_dev->dev->ifindex,
};
struct nlattr *attrs[RTA_MAX+1] = {
[RTA_DST] = (struct nlattr *) &dst_attr,
[RTA_PREFSRC] = (struct nlattr * ) &prefsrc_attr,
[RTA_OIF] = (struct nlattr *) &oif_attr,
};

memset(&req.rtm, 0, sizeof(req.rtm));
memset(&rta, 0, sizeof(rta));

if (type == RTN_UNICAST)
tb = dn_fib_get_table(RT_MIN_TABLE, 1);
Expand All @@ -591,14 +614,10 @@ static void fib_magic(int cmd, int type, __le16 dst, int dst_len, struct dn_ifad
req.rtm.rtm_scope = (type != RTN_LOCAL ? RT_SCOPE_LINK : RT_SCOPE_HOST);
req.rtm.rtm_type = type;

rta.rta_dst = &dst;
rta.rta_prefsrc = &ifa->ifa_local;
rta.rta_oif = &ifa->ifa_dev->dev->ifindex;

if (cmd == RTM_NEWROUTE)
tb->insert(tb, &req.rtm, &rta, &req.nlh, NULL);
tb->insert(tb, &req.rtm, attrs, &req.nlh, NULL);
else
tb->delete(tb, &req.rtm, &rta, &req.nlh, NULL);
tb->delete(tb, &req.rtm, attrs, &req.nlh, NULL);
}

static void dn_fib_add_ifaddr(struct dn_ifaddr *ifa)
Expand Down
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