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authorHarald Welte <laforge@netfilter.org>2005-10-10 20:52:19 -0700
committerDavid S. Miller <davem@davemloft.net>2005-10-10 20:52:19 -0700
commitebe0bbf06c9e03613bdcb6b5a704595a9344b7ff (patch)
tree33453cb2cd33095e3a226d0866bdfe1019473646
parentf40863cec87464f3f4ec3a6c00e3fda3bbb0c91b (diff)
[NETFILTER] nfnetlink: use highest bit of nfa_type to indicate nested TLV
As Henrik Nordstrom pointed out, all our efforts with "split endian" (i.e. host byte order tags, net byte order values) are useless, unless a parser can determine whether an attribute is nested or not. This patch steals the highest bit of nfattr.nfa_type to indicate whether the data payload contains a nested nfattr (1) or not (0). This will break userspace compatibility, but luckily no kernel with nfnetlink was released so far. Signed-off-by: Harald Welte <laforge@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/netfilter/nfnetlink.h12
-rw-r--r--net/netfilter/nfnetlink.c4
2 files changed, 10 insertions, 6 deletions
diff --git a/include/linux/netfilter/nfnetlink.h b/include/linux/netfilter/nfnetlink.h
index 1d5b10ae239..f08e870100f 100644
--- a/include/linux/netfilter/nfnetlink.h
+++ b/include/linux/netfilter/nfnetlink.h
@@ -41,11 +41,15 @@ enum nfnetlink_groups {
struct nfattr
{
u_int16_t nfa_len;
- u_int16_t nfa_type;
+ u_int16_t nfa_type; /* we use 15 bits for the type, and the highest
+ * bit to indicate whether the payload is nested */
} __attribute__ ((packed));
-/* FIXME: Shamelessly copy and pasted from rtnetlink.h, it's time
- * to put this in a generic file */
+/* FIXME: Apart from NFNL_NFA_NESTED shamelessly copy and pasted from
+ * rtnetlink.h, it's time to put this in a generic file */
+
+#define NFNL_NFA_NEST 0x8000
+#define NFA_TYPE(attr) ((attr)->nfa_type & 0x7fff)
#define NFA_ALIGNTO 4
#define NFA_ALIGN(len) (((len) + NFA_ALIGNTO - 1) & ~(NFA_ALIGNTO - 1))
@@ -59,7 +63,7 @@ struct nfattr
#define NFA_PAYLOAD(nfa) ((int)((nfa)->nfa_len) - NFA_LENGTH(0))
#define NFA_NEST(skb, type) \
({ struct nfattr *__start = (struct nfattr *) (skb)->tail; \
- NFA_PUT(skb, type, 0, NULL); \
+ NFA_PUT(skb, (NFNL_NFA_NEST | type), 0, NULL); \
__start; })
#define NFA_NEST_END(skb, start) \
({ (start)->nfa_len = ((skb)->tail - (unsigned char *) (start)); \
diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 1caaca06f69..4bc27a6334c 100644
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -133,7 +133,7 @@ int nfattr_parse(struct nfattr *tb[], int maxattr, struct nfattr *nfa, int len)
memset(tb, 0, sizeof(struct nfattr *) * maxattr);
while (NFA_OK(nfa, len)) {
- unsigned flavor = nfa->nfa_type;
+ unsigned flavor = NFA_TYPE(nfa);
if (flavor && flavor <= maxattr)
tb[flavor-1] = nfa;
nfa = NFA_NEXT(nfa, len);
@@ -177,7 +177,7 @@ nfnetlink_check_attributes(struct nfnetlink_subsystem *subsys,
int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
while (NFA_OK(attr, attrlen)) {
- unsigned flavor = attr->nfa_type;
+ unsigned flavor = NFA_TYPE(attr);
if (flavor) {
if (flavor > attr_count)
return -EINVAL;