[netsniff-ng] [PATCH] flowtop: Replace single linked list by list_head from list.h
list.h provides generic Linux-like linked list API which also supports
RCU list operations.
Also additionally was removed the spinlock which is not needed for
RCU-list operations, for the list_del_rcu(...) case it is needed
additionally call call_rcu(...) before free the flow entry.
Because of full RCU support now flows are freed after grace-period
(after presenter leaves RCU lock) via calling call_rcu(), because
of that for the new entries we return NFCT_CB_STOLEN to tell conntrack
API do not automatically free received nfct_conntrack object, it will be
freed by us via call_rcu(...) therefor no need to use nfct_clone(n).
Signed-off-by: Vadim Kochan
---
flowtop.c | 148 --
1 file changed, 47 insertions(+), 101 deletions(-)
diff --git a/flowtop.c b/flowtop.c
index f48f5c8..3cee0ec 100644
--- a/flowtop.c
+++ b/flowtop.c
@@ -36,7 +36,6 @@
#include "lookup.h"
#include "geoip.h"
#include "built_in.h"
-#include "locking.h"
#include "pkt_buff.h"
#include "screen.h"
#include "proc.h"
@@ -51,6 +50,9 @@
#endif
struct flow_entry {
+ struct list_head entry;
+ struct rcu_head rcu;
+
uint32_t flow_id, use, status;
uint8_t l3_proto, l4_proto;
uint32_t ip4_src_addr, ip4_dst_addr;
@@ -65,7 +67,6 @@ struct flow_entry {
char city_src[128], city_dst[128];
char rev_dns_src[256], rev_dns_dst[256];
char procname[256];
- struct flow_entry *next;
int inode;
unsigned int procnum;
bool is_visible;
@@ -78,8 +79,7 @@ struct flow_entry {
};
struct flow_list {
- struct flow_entry *head;
- struct spinlock lock;
+ struct list_head head;
};
enum flow_direction {
@@ -360,10 +360,16 @@ static inline void flow_entry_xfree(struct flow_entry *n)
xfree(n);
}
+static void flow_entry_xfree_rcu(struct rcu_head *head)
+{
+ struct flow_entry *n = container_of(head, struct flow_entry, rcu);
+
+ flow_entry_xfree(n);
+}
+
static inline void flow_list_init(struct flow_list *fl)
{
- fl->head = NULL;
- spinlock_init(&fl->lock);
+ INIT_LIST_HEAD(&fl->head);
}
static inline bool nfct_is_dns(const struct nf_conntrack *ct)
@@ -374,7 +380,7 @@ static inline bool nfct_is_dns(const struct nf_conntrack
*ct)
return ntohs(port_src) == 53 || ntohs(port_dst) == 53;
}
-static void flow_list_new_entry(struct flow_list *fl, const struct
nf_conntrack *ct)
+static int flow_list_new_entry(struct flow_list *fl, struct nf_conntrack *ct)
{
struct flow_entry *n;
@@ -382,94 +388,56 @@ static void flow_list_new_entry(struct flow_list *fl,
const struct nf_conntrack
* use it to resolve reverse dns.
*/
if (nfct_is_dns(ct))
- return;
+ return NFCT_CB_CONTINUE;
n = flow_entry_xalloc();
- n->ct = nfct_clone(ct);
+ n->ct = ct;
flow_entry_update_time(n);
flow_entry_from_ct(n, ct);
flow_entry_get_extended(n);
- rcu_assign_pointer(n->next, fl->head);
- rcu_assign_pointer(fl->head, n);
+ list_add_rcu(&n->entry, &fl->head);
n->is_visible = true;
+
+ return NFCT_CB_STOLEN;
}
-static struct flow_entry *flow_list_find_id(struct flow_list *fl,
- uint32_t id)
+static struct flow_entry *flow_list_find_id(struct flow_list *fl, uint32_t id)
{
- struct flow_entry *n = rcu_dereference(fl->head);
+ struct flow_entry *n;
- while (n != NULL) {
+ list_for_each_entry_rcu(n, &fl->head, entry) {
if (n->flow_id == id)
return n;
-
- n = rcu_dereference(n->next);
}
return NULL;
}
-static struct flow_entry *flow_list_find_prev_id(const struct flow_list *fl,
-uint32_t id)
+static int flow_list_del_entry(struct flow_list *fl, const struct nf_conntrack
*ct)
{
- struct flow_entry *prev = rcu_dereference(fl->head), *next;
-
- if (prev->flow_id == id)
- return NULL;
-
- while ((next = rcu_dereference(prev->next)) != NULL) {
- if (next->flow_id == id)
- return prev;
+ struct flow_entry *n;
- prev = next;
+ n = flow_list_find_id(fl, nfct_get_attr_u32(ct, ATTR_ID));
+ if (n) {
+ list_del_rcu(&n->entry);
+ call_rcu(&n->rcu, flow_entry_xfree_rcu);
}
- return NULL;
-}
-
-static void flow_list_destroy_entry(struct flow_list *fl,
- const struct nf_conntrack *ct)
-{
- struct flow_entry *n1, *n2;
- uint32_t id = nfct_get_attr_u32(ct, ATTR_ID);
-
- n1 = flow_list_find_id(fl, id);
- if (n1) {
- n2 = flow_list_find_prev_id(fl, id);
- if (n2) {
- rcu_assign_pointer(n2->next, n1->next);
-
[netsniff-ng] [PATCH] flowtop: Replace single linked list by list_head from list.h
list.h provides generic Linux-like linked list API which also supports
RCU list operations.
Also additionally was removed the spinlock which is not needed for
RCU-list operations, for the list_del_rcu(...) case it is needed
additionally call synchronize_rcu(...) before free the flow entry.
Because of full RCU support now flows are freed after grace-period via
calling synchronize_rcu() and these removed-and-ready-to-free entries
are kept in separate struct list_head.
Signed-off-by: Vadim Kochan
---
flowtop.c | 121 +++---
1 file changed, 44 insertions(+), 77 deletions(-)
diff --git a/flowtop.c b/flowtop.c
index f48f5c8..a5ac2bb 100644
--- a/flowtop.c
+++ b/flowtop.c
@@ -51,6 +51,9 @@
#endif
struct flow_entry {
+ struct list_head entry;
+ struct list_head free;
+
uint32_t flow_id, use, status;
uint8_t l3_proto, l4_proto;
uint32_t ip4_src_addr, ip4_dst_addr;
@@ -65,7 +68,6 @@ struct flow_entry {
char city_src[128], city_dst[128];
char rev_dns_src[256], rev_dns_dst[256];
char procname[256];
- struct flow_entry *next;
int inode;
unsigned int procnum;
bool is_visible;
@@ -78,8 +80,8 @@ struct flow_entry {
};
struct flow_list {
- struct flow_entry *head;
- struct spinlock lock;
+ struct list_head head;
+ struct list_head free;
};
enum flow_direction {
@@ -355,15 +357,15 @@ static inline struct flow_entry *flow_entry_xalloc(void)
static inline void flow_entry_xfree(struct flow_entry *n)
{
if (n->ct)
- nfct_destroy(n->ct);
+ xfree(n->ct);
xfree(n);
}
static inline void flow_list_init(struct flow_list *fl)
{
- fl->head = NULL;
- spinlock_init(&fl->lock);
+ INIT_LIST_HEAD(&fl->head);
+ INIT_LIST_HEAD(&fl->free);
}
static inline bool nfct_is_dns(const struct nf_conntrack *ct)
@@ -392,84 +394,60 @@ static void flow_list_new_entry(struct flow_list *fl,
const struct nf_conntrack
flow_entry_from_ct(n, ct);
flow_entry_get_extended(n);
- rcu_assign_pointer(n->next, fl->head);
- rcu_assign_pointer(fl->head, n);
+ list_add_rcu(&n->entry, &fl->head);
n->is_visible = true;
}
-static struct flow_entry *flow_list_find_id(struct flow_list *fl,
- uint32_t id)
+static struct flow_entry *flow_list_find_id(struct flow_list *fl, uint32_t id)
{
- struct flow_entry *n = rcu_dereference(fl->head);
+ struct flow_entry *n;
- while (n != NULL) {
+ list_for_each_entry_rcu(n, &fl->head, entry) {
if (n->flow_id == id)
return n;
-
- n = rcu_dereference(n->next);
}
return NULL;
}
-static struct flow_entry *flow_list_find_prev_id(const struct flow_list *fl,
-uint32_t id)
+static void flow_list_del_entry(struct flow_list *fl, const struct
nf_conntrack *ct)
{
- struct flow_entry *prev = rcu_dereference(fl->head), *next;
-
- if (prev->flow_id == id)
- return NULL;
-
- while ((next = rcu_dereference(prev->next)) != NULL) {
- if (next->flow_id == id)
- return prev;
+ struct flow_entry *n;
- prev = next;
+ n = flow_list_find_id(fl, nfct_get_attr_u32(ct, ATTR_ID));
+ if (n) {
+ list_del_rcu(&n->entry);
+ list_add_rcu(&n->free, &fl->free);
}
-
- return NULL;
}
-static void flow_list_destroy_entry(struct flow_list *fl,
- const struct nf_conntrack *ct)
+static void flow_list_clear(struct flow_list *fl)
{
- struct flow_entry *n1, *n2;
- uint32_t id = nfct_get_attr_u32(ct, ATTR_ID);
-
- n1 = flow_list_find_id(fl, id);
- if (n1) {
- n2 = flow_list_find_prev_id(fl, id);
- if (n2) {
- rcu_assign_pointer(n2->next, n1->next);
- n1->next = NULL;
-
- flow_entry_xfree(n1);
- } else {
- struct flow_entry *next = fl->head->next;
+ struct flow_entry *n, *tmp;
- flow_entry_xfree(fl->head);
- fl->head = next;
- }
+ list_for_each_entry_safe(n, tmp, &fl->head, entry) {
+ list_del_rcu(&n->entry);
+ list_add_rcu(&n->free, &fl->free);
}
}
-static void flow_list_destroy(struct flow_list *fl)
+static void flow_list_free(struct flow_list *fl)
{
- struct flow_entry *n;
+ struct flow_entry *n, *tmp;
synchronize_rcu();
- spinlock_lock(&flow_list.lock);
- while (fl->head != NULL) {
- n = rcu_dereference(fl->head->next);
- fl->head->next = NULL;
-
- flow_entry_xfre
