ll_map: add name and index hash

Make ll_ functions faster by having a name hash, and allow
for deletion. Also, allow them to work without calling ll_init_map.

diff --git a/include/hlist.h b/include/hlist.h
new file mode 100644 (file)
index 0000000..4e8de9e
--- /dev/null
+++ b/include/hlist.h
@@ -0,0 +1,56 @@
+#ifndef __HLIST_H__
+#define __HLIST_H__ 1
+/* Hash list stuff from kernel */
+
+#include <stddef.h>
+
+#define container_of(ptr, type, member) ({                     \
+       const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
+       (type *)( (char *)__mptr - offsetof(type,member) );})
+
+struct hlist_head {
+       struct hlist_node *first;
+};
+
+struct hlist_node {
+       struct hlist_node *next, **pprev;
+};
+
+static inline void hlist_del(struct hlist_node *n)
+{
+       struct hlist_node *next = n->next;
+       struct hlist_node **pprev = n->pprev;
+       *pprev = next;
+       if (next)
+               next->pprev = pprev;
+}
+
+static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
+{
+       struct hlist_node *first = h->first;
+       n->next = first;
+       if (first)
+               first->pprev = &n->next;
+       h->first = n;
+       n->pprev = &h->first;
+}
+
+#define hlist_for_each(pos, head) \
+       for (pos = (head)->first; pos ; pos = pos->next)
+
+
+#define hlist_for_each_safe(pos, n, head) \
+       for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
+            pos = n)
+
+#define hlist_entry_safe(ptr, type, member) \
+       ({ typeof(ptr) ____ptr = (ptr); \
+          ____ptr ? hlist_entry(____ptr, type, member) : NULL; \
+       })
+
+#define hlist_for_each_entry(pos, head, member)                                \
+       for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\
+            pos;                                                       \
+            pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
+
+#endif /* __HLIST_H__ */

diff --git a/include/ll_map.h b/include/ll_map.h
index c4d5c6d1b0188a59840648a162d28e472cdc5895..f1dda39b7604f69b981d6e93fd1e8c83c0f9ff54 100644 (file)
--- a/include/ll_map.h
+++ b/include/ll_map.h
@@ -3,7 +3,8 @@
 
 extern int ll_remember_index(const struct sockaddr_nl *who,
                             struct nlmsghdr *n, void *arg);
-extern int ll_init_map(struct rtnl_handle *rth);
+
+extern void ll_init_map(struct rtnl_handle *rth);
 extern unsigned ll_name_to_index(const char *name);
 extern const char *ll_index_to_name(unsigned idx);
 extern const char *ll_idx_n2a(unsigned idx, char *buf);

diff --git a/lib/ll_map.c b/lib/ll_map.c
index e9ae129611e581faa12f37ae9bbd59ea95ddf9d8..fd7db550f85eb2b5cd2b43555fd7844c9086fc2b 100644 (file)
--- a/lib/ll_map.c
+++ b/lib/ll_map.c
@@ -22,10 +22,11 @@
 
 #include "libnetlink.h"
 #include "ll_map.h"
+#include "hlist.h"
 
-struct ll_cache
-{
-       struct ll_cache   *idx_next;
+struct ll_cache {
+       struct hlist_node idx_hash;
+       struct hlist_node name_hash;
        unsigned        flags;
        int             index;
        unsigned short  type;
@@ -33,49 +34,107 @@ struct ll_cache
 };
 
 #define IDXMAP_SIZE    1024
-static struct ll_cache *idx_head[IDXMAP_SIZE];
+static struct hlist_head idx_head[IDXMAP_SIZE];
+static struct hlist_head name_head[IDXMAP_SIZE];
 
-static inline struct ll_cache *idxhead(int idx)
+static struct ll_cache *ll_get_by_index(unsigned index)
 {
-       return idx_head[idx & (IDXMAP_SIZE - 1)];
+       struct hlist_node *n;
+       unsigned h = index & (IDXMAP_SIZE - 1);
+
+       hlist_for_each(n, &idx_head[h]) {
+               struct ll_cache *im
+                       = container_of(n, struct ll_cache, idx_hash);
+               if (im->index == index)
+                       return im;
+       }
+
+       return NULL;
+}
+
+static unsigned namehash(const char *str)
+{
+       unsigned hash = 5381;
+
+       while (*str)
+               hash = ((hash << 5) + hash) + *str++; /* hash * 33 + c */
+
+       return hash;
+}
+
+static struct ll_cache *ll_get_by_name(const char *name)
+{
+       struct hlist_node *n;
+       unsigned h = namehash(name) & (IDXMAP_SIZE - 1);
+
+       hlist_for_each(n, &name_head[h]) {
+               struct ll_cache *im
+                       = container_of(n, struct ll_cache, name_hash);
+
+               if (strncmp(im->name, name, IFNAMSIZ) == 0)
+                       return im;
+       }
+
+       return NULL;
 }
 
 int ll_remember_index(const struct sockaddr_nl *who,
                      struct nlmsghdr *n, void *arg)
 {
-       int h;
+       unsigned int h;
+       const char *ifname;
        struct ifinfomsg *ifi = NLMSG_DATA(n);
-       struct ll_cache *im, **imp;
+       struct ll_cache *im;
        struct rtattr *tb[IFLA_MAX+1];
 
-       if (n->nlmsg_type != RTM_NEWLINK)
+       if (n->nlmsg_type != RTM_NEWLINK && n->nlmsg_type != RTM_DELLINK)
                return 0;
 
        if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi)))
                return -1;
 
+       im = ll_get_by_index(ifi->ifi_index);
+       if (n->nlmsg_type == RTM_DELLINK) {
+               if (im) {
+                       hlist_del(&im->name_hash);
+                       hlist_del(&im->idx_hash);
+                       free(im);
+               }
+               return 0;
+       }
+
        memset(tb, 0, sizeof(tb));
        parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), IFLA_PAYLOAD(n));
-       if (tb[IFLA_IFNAME] == NULL)
+       ifname = rta_getattr_str(tb[IFLA_IFNAME]);
+       if (ifname == NULL)
                return 0;
 
-       h = ifi->ifi_index & (IDXMAP_SIZE - 1);
-       for (imp = &idx_head[h]; (im=*imp)!=NULL; imp = &im->idx_next)
-               if (im->index == ifi->ifi_index)
-                       break;
-
-       if (im == NULL) {
-               im = malloc(sizeof(*im));
-               if (im == NULL)
-                       return 0;
-               im->idx_next = *imp;
-               im->index = ifi->ifi_index;
-               *imp = im;
+       if (im) {
+               /* change to existing entry */
+               if (strcmp(im->name, ifname) != 0) {
+                       hlist_del(&im->name_hash);
+                       h = namehash(ifname) & (IDXMAP_SIZE - 1);
+                       hlist_add_head(&im->name_hash, &name_head[h]);
+               }
+
+               im->flags = ifi->ifi_flags;
+               return 0;
        }
 
+       im = malloc(sizeof(*im));
+       if (im == NULL)
+               return 0;
+       im->index = ifi->ifi_index;
+       strcpy(im->name, ifname);
        im->type = ifi->ifi_type;
        im->flags = ifi->ifi_flags;
-       strcpy(im->name, RTA_DATA(tb[IFLA_IFNAME]));
+
+       h = ifi->ifi_index & (IDXMAP_SIZE - 1);
+       hlist_add_head(&im->idx_hash, &idx_head[h]);
+
+       h = namehash(ifname) & (IDXMAP_SIZE - 1);
+       hlist_add_head(&im->name_hash, &name_head[h]);
+
        return 0;
 }
 
@@ -86,15 +145,16 @@ const char *ll_idx_n2a(unsigned idx, char *buf)
        if (idx == 0)
                return "*";
 
-       for (im = idxhead(idx); im; im = im->idx_next)
-               if (im->index == idx)
-                       return im->name;
+       im = ll_get_by_index(idx);
+       if (im)
+               return im->name;
+
+       if (if_indextoname(idx, buf) == NULL)
+               snprintf(buf, IFNAMSIZ, "if%d", idx);
 
-       snprintf(buf, IFNAMSIZ, "if%d", idx);
        return buf;
 }
 
-
 const char *ll_index_to_name(unsigned idx)
 {
        static char nbuf[IFNAMSIZ];
@@ -108,10 +168,9 @@ int ll_index_to_type(unsigned idx)
 
        if (idx == 0)
                return -1;
-       for (im = idxhead(idx); im; im = im->idx_next)
-               if (im->index == idx)
-                       return im->type;
-       return -1;
+
+       im = ll_get_by_index(idx);
+       return im ? im->type : -1;
 }
 
 unsigned ll_index_to_flags(unsigned idx)
@@ -121,35 +180,21 @@ unsigned ll_index_to_flags(unsigned idx)
        if (idx == 0)
                return 0;
 
-       for (im = idxhead(idx); im; im = im->idx_next)
-               if (im->index == idx)
-                       return im->flags;
-       return 0;
+       im = ll_get_by_index(idx);
+       return im ? im->flags : -1;
 }
 
 unsigned ll_name_to_index(const char *name)
 {
-       static char ncache[IFNAMSIZ];
-       static int icache;
-       struct ll_cache *im;
-       int i;
+       const struct ll_cache *im;
        unsigned idx;
 
        if (name == NULL)
                return 0;
 
-       if (icache && strcmp(name, ncache) == 0)
-               return icache;
-
-       for (i=0; i<IDXMAP_SIZE; i++) {
-               for (im = idx_head[i]; im; im = im->idx_next) {
-                       if (strcmp(im->name, name) == 0) {
-                               icache = im->index;
-                               strcpy(ncache, name);
-                               return im->index;
-                       }
-               }
-       }
+       im = ll_get_by_name(name);
+       if (im)
+               return im->index;
 
        idx = if_nametoindex(name);
        if (idx == 0)
@@ -157,12 +202,12 @@ unsigned ll_name_to_index(const char *name)
        return idx;
 }
 
-int ll_init_map(struct rtnl_handle *rth)
+void ll_init_map(struct rtnl_handle *rth)
 {
        static int initialized;
 
        if (initialized)
-               return 0;
+               return;
 
        if (rtnl_wilddump_request(rth, AF_UNSPEC, RTM_GETLINK) < 0) {
                perror("Cannot send dump request");
@@ -175,6 +220,4 @@ int ll_init_map(struct rtnl_handle *rth)
        }
 
        initialized = 1;
-
-       return 0;
 }