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Clearly comment the assumptions that allow us to cast a

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'struct radix_node *' to a 'struct rtentry *' in this code,
and introduce a macro, RNTORT(), to do this type conversion.
This commit is contained in:
Luigi Rizzo 2004-04-21 15:16:08 +00:00
parent e267671499
commit d6941ce931
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=128524
1 changed files with 27 additions and 17 deletions
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44
sys/net/route.c
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@ -56,6 +56,21 @@ static void rt_maskedcopy(struct sockaddr *,
struct sockaddr *, struct sockaddr *);
static void rtable_init(void **);
/* compare two sockaddr structures */
#define sa_equal(a1, a2) (bcmp((a1), (a2), (a1)->sa_len) == 0)
/*
* Convert a 'struct radix_node *' to a 'struct rtentry *'.
* The operation can be done safely (in this code) because a
* 'struct rtentry' starts with two 'struct radix_node''s, the first
* one representing leaf nodes in the routing tree, which is
* what the code in radix.c passes us as a 'struct radix_node'.
*
* But because there are a lot of assumptions in this conversion,
* do not cast explicitly, but always use the macro below.
*/
#define RNTORT(p) ((struct rtentry *)(p))
static void
rtable_init(void **table)
{
@ -131,7 +146,7 @@ rtalloc1(struct sockaddr *dst, int report, u_long ignflags)
* If we find it and it's not the root node, then
* get a refernce on the rtentry associated.
*/
newrt = rt = (struct rtentry *)rn;
newrt = rt = RNTORT(rn);
nflags = rt->rt_flags & ~ignflags;
if (report && (nflags & RTF_CLONING)) {
/*
@ -284,8 +299,6 @@ rtfree(struct rtentry *rt)
RT_UNLOCK(rt);
}
/* compare two sockaddr structures */
#define sa_equal(a1, a2) (bcmp((a1), (a2), (a1)->sa_len) == 0)
/*
* Force a routing table entry to the specified
@ -569,7 +582,7 @@ rtexpunge(struct rtentry *rt)
}
KASSERT((rn->rn_flags & (RNF_ACTIVE | RNF_ROOT)) == 0,
("unexpected flags 0x%x", rn->rn_flags));
KASSERT(rt == (struct rtentry *)rn,
KASSERT(rt == RNTORT(rn),
("lookup mismatch, rt %p rn %p", rt, rn));
rt->rt_flags &= ~RTF_UP;
@ -588,8 +601,7 @@ rtexpunge(struct rtentry *rt)
* we held its last reference.
*/
if (rt->rt_gwroute) {
struct rtentry *gwrt = rt->rt_gwroute;
RTFREE(gwrt);
RTFREE(rt->rt_gwroute);
rt->rt_gwroute = NULL;
}
@ -654,7 +666,7 @@ rtrequest1(int req, struct rt_addrinfo *info, struct rtentry **ret_nrt)
senderr(ESRCH);
if (rn->rn_flags & (RNF_ACTIVE | RNF_ROOT))
panic ("rtrequest delete");
rt = (struct rtentry *)rn;
rt = RNTORT(rn);
RT_LOCK(rt);
RT_ADDREF(rt);
rt->rt_flags &= ~RTF_UP;
@ -675,8 +687,7 @@ rtrequest1(int req, struct rt_addrinfo *info, struct rtentry **ret_nrt)
* we held its last reference.
*/
if (rt->rt_gwroute) {
struct rtentry *gwrt = rt->rt_gwroute;
RTFREE(gwrt);
RTFREE(rt->rt_gwroute);
rt->rt_gwroute = NULL;
}
@ -687,8 +698,9 @@ rtrequest1(int req, struct rt_addrinfo *info, struct rtentry **ret_nrt)
ifa->ifa_rtrequest(RTM_DELETE, rt, info);
/*
* one more rtentry floating around that is not
* linked to the routing table.
* One more rtentry floating around that is not
* linked to the routing table. rttrash will be decremented
* when RTFREE(rt) is eventually called.
*/
rttrash++;
@ -886,8 +898,7 @@ rtrequest1(int req, struct rt_addrinfo *info, struct rtentry **ret_nrt)
static int
rt_fixdelete(struct radix_node *rn, void *vp)
{
/* The cast is safe because *rt starts with a struct radix_node. */
struct rtentry *rt = (struct rtentry *)rn;
struct rtentry *rt = RNTORT(rn);
struct rtentry *rt0 = vp;
if (rt->rt_parent == rt0 &&
@ -915,8 +926,7 @@ rt_fixdelete(struct radix_node *rn, void *vp)
static int
rt_fixchange(struct radix_node *rn, void *vp)
{
/* The cast is safe because *rt starts with a struct radix_node. */
struct rtentry *rt = (struct rtentry *)rn;
struct rtentry *rt = RNTORT(rn);
struct rtfc_arg *ap = vp;
struct rtentry *rt0 = ap->rt0;
struct radix_node_head *rnh = ap->rnh;
@ -1048,7 +1058,7 @@ rt_setgate(struct rtentry *rt, struct sockaddr *dst, struct sockaddr *gate)
rt->rt_gwroute = gwrt;
if (rt->rt_gwroute == rt) {
RTFREE_LOCKED(rt->rt_gwroute);
rt->rt_gwroute = 0;
rt->rt_gwroute = NULL;
return EDQUOT; /* failure */
}
if (rt->rt_gwroute != NULL)
@ -1148,7 +1158,7 @@ rtinit(struct ifaddr *ifa, int cmd, int flags)
RADIX_NODE_HEAD_LOCK(rnh);
error = ((rn = rnh->rnh_lookup(dst, netmask, rnh)) == NULL ||
(rn->rn_flags & RNF_ROOT) ||
((struct rtentry *)rn)->rt_ifa != ifa ||
RNTORT(rn)->rt_ifa != ifa ||
!sa_equal((struct sockaddr *)rn->rn_key, dst));
RADIX_NODE_HEAD_UNLOCK(rnh);
if (error) {