[NET]: show bound packet types

Show what protocols are bound to what packet types in /proc/net/ptype
Uses kallsyms to decode function pointers if possible.
Example:
	Type Device      Function
	ALL  eth1     packet_rcv_spkt+0x0
	0800          ip_rcv+0x0
	0806          arp_rcv+0x0
	86dd          :ipv6:ipv6_rcv+0x0

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 134 insertions, 0 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 8ddc2ab23142..3af0bdc86491 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2216,6 +2216,135 @@ static const struct file_operations softnet_seq_fops = {
         .release = seq_release,
 };
 
+static void *ptype_get_idx(loff_t pos)
+{
+        struct packet_type *pt = NULL;
+        loff_t i = 0;
+        int t;
+
+        list_for_each_entry_rcu(pt, &ptype_all, list) {
+                if (i == pos)
+                        return pt;
+                ++i;
+        }
+
+        for (t = 0; t < 16; t++) {
+                list_for_each_entry_rcu(pt, &ptype_base[t], list) {
+                        if (i == pos)
+                                return pt;
+                        ++i;
+                }
+        }
+        return NULL;
+}
+
+static void *ptype_seq_start(struct seq_file *seq, loff_t *pos)
+{
+        rcu_read_lock();
+        return *pos ? ptype_get_idx(*pos - 1) : SEQ_START_TOKEN;
+}
+
+static void *ptype_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+        struct packet_type *pt;
+        struct list_head *nxt;
+        int hash;
+
+        ++*pos;
+        if (v == SEQ_START_TOKEN)
+                return ptype_get_idx(0);
+
+        pt = v;
+        nxt = pt->list.next;
+        if (pt->type == htons(ETH_P_ALL)) {
+                if (nxt != &ptype_all)
+                        goto found;
+                hash = 0;
+                nxt = ptype_base[0].next;
+        } else
+                hash = ntohs(pt->type) & 15;
+
+        while (nxt == &ptype_base[hash]) {
+                if (++hash >= 16)
+                        return NULL;
+                nxt = ptype_base[hash].next;
+        }
+found:
+        return list_entry(nxt, struct packet_type, list);
+}
+
+static void ptype_seq_stop(struct seq_file *seq, void *v)
+{
+        rcu_read_unlock();
+}
+
+static void ptype_seq_decode(struct seq_file *seq, void *sym)
+{
+#ifdef CONFIG_KALLSYMS
+        unsigned long offset = 0, symsize;
+        const char *symname;
+        char *modname;
+        char namebuf[128];
+
+        symname = kallsyms_lookup((unsigned long)sym, &symsize, &offset,
+                                  &modname, namebuf);
+
+        if (symname) {
+                char *delim = ":";
+
+                if (!modname)
+                        modname = delim = "";
+                seq_printf(seq, "%s%s%s%s+0x%lx", delim, modname, delim,
+                           symname, offset);
+                return;
+        }
+#endif
+
+        seq_printf(seq, "[%p]", sym);
+}
+
+static int ptype_seq_show(struct seq_file *seq, void *v)
+{
+        struct packet_type *pt = v;
+
+        if (v == SEQ_START_TOKEN)
+                seq_puts(seq, "Type Device      Function\n");
+        else {
+                if (pt->type == htons(ETH_P_ALL))
+                        seq_puts(seq, "ALL ");
+                else
+                        seq_printf(seq, "%04x", ntohs(pt->type));
+
+                seq_printf(seq, " %-8s ",
+                           pt->dev ? pt->dev->name : "");
+                ptype_seq_decode(seq,  pt->func);
+                seq_putc(seq, '\n');
+        }
+
+        return 0;
+}
+
+static const struct seq_operations ptype_seq_ops = {
+        .start = ptype_seq_start,
+        .next  = ptype_seq_next,
+        .stop  = ptype_seq_stop,
+        .show  = ptype_seq_show,
+};
+
+static int ptype_seq_open(struct inode *inode, struct file *file)
+{
+        return seq_open(file, &ptype_seq_ops);
+}
+
+static const struct file_operations ptype_seq_fops = {
+        .owner   = THIS_MODULE,
+        .open    = ptype_seq_open,
+        .read    = seq_read,
+        .llseek  = seq_lseek,
+        .release = seq_release,
+};
+
+
 #ifdef CONFIG_WIRELESS_EXT
 extern int wireless_proc_init(void);
 #else
@@ -2230,6 +2359,9 @@ static int __init dev_proc_init(void)
                 goto out;
         if (!proc_net_fops_create("softnet_stat", S_IRUGO, &softnet_seq_fops))
                 goto out_dev;
+        if (!proc_net_fops_create("ptype", S_IRUGO, &ptype_seq_fops))
+                goto out_dev2;
+
         if (wireless_proc_init())
                 goto out_softnet;
         rc = 0;
@@ -2237,6 +2369,8 @@ out:
         return rc;
 out_softnet:
         proc_net_remove("softnet_stat");
+out_dev2:
+        proc_net_remove("ptype");
 out_dev:
         proc_net_remove("dev");
         goto out;