New API routine slirp_neighbor_info

This will be called from QEMU to dump the ARP/NDP tables.

ndpentry.eth_addr type changed from unsigned char to uint8_t
to be consistent with other macaddr objects.
Ditto for slirp_arphdr.{ar_sha,ar_tha}.

Signed-off-by: Doug Evans <dje@google.com>

4 files changed, 50 insertions, 4 deletions

diff --git a/src/libslirp.h b/src/libslirp.h
index 4afb7d6..b52b63d 100644
--- a/src/libslirp.h
+++ b/src/libslirp.h
@@ -205,6 +205,9 @@ int slirp_remove_guestfwd(Slirp *slirp, struct in_addr guest_addr,
 /* Return a human-readable state of the slirp stack */
 char *slirp_connection_info(Slirp *slirp);
 
+/* Return a human-readable state of the NDP/ARP tables */
+char *slirp_neighbor_info(Slirp *slirp);
+
 /* Save the slirp state through the write_cb. The opaque pointer is passed as
  * such to the write_cb. */
 void slirp_state_save(Slirp *s, SlirpWriteCb write_cb, void *opaque);
diff --git a/src/libslirp.map b/src/libslirp.map
index c0113c9..20a17ac 100644
--- a/src/libslirp.map
+++ b/src/libslirp.map
@@ -32,4 +32,5 @@ SLIRP_4.2 {
 SLIRP_4.5 {
     slirp_add_ipv6_hostfwd;
     slirp_remove_ipv6_hostfwd;
+    slirp_neighbor_info;
 } SLIRP_4.2;
diff --git a/src/misc.c b/src/misc.c
index 12487b2..48f180b 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -377,6 +377,48 @@ char *slirp_connection_info(Slirp *slirp)
     return g_string_free(str, FALSE);
 }
 
+char *slirp_neighbor_info(Slirp *slirp)
+{
+    GString *str = g_string_new(NULL);
+    ArpTable *arp_table = &slirp->arp_table;
+    NdpTable *ndp_table = &slirp->ndp_table;
+    char ip_addr[INET6_ADDRSTRLEN];
+    char eth_addr[ETH_ADDRSTRLEN];
+    const char *ip;
+
+    g_string_append_printf(str, "  %5s  %-17s  %s\n",
+                           "Table", "MacAddr", "IP Address");
+
+    for (int i = 0; i < ARP_TABLE_SIZE; ++i) {
+        struct in_addr addr;
+        addr.s_addr = arp_table->table[i].ar_sip;
+        if (!addr.s_addr) {
+            continue;
+        }
+        ip = inet_ntop(AF_INET, &addr, ip_addr, sizeof(ip_addr));
+        g_assert(ip != NULL);
+        g_string_append_printf(str, "  %5s  %-17s  %s\n", "ARP",
+                               slirp_ether_ntoa(arp_table->table[i].ar_sha,
+                                                eth_addr, sizeof(eth_addr)),
+                               ip);
+    }
+
+    for (int i = 0; i < NDP_TABLE_SIZE; ++i) {
+        if (in6_zero(&ndp_table->table[i].ip_addr)) {
+            continue;
+        }
+        ip = inet_ntop(AF_INET6, &ndp_table->table[i].ip_addr, ip_addr,
+                       sizeof(ip_addr));
+        g_assert(ip != NULL);
+        g_string_append_printf(str, "  %5s  %-17s  %s\n", "NDP",
+                               slirp_ether_ntoa(ndp_table->table[i].eth_addr,
+                                                eth_addr, sizeof(eth_addr)),
+                               ip);
+    }
+
+    return g_string_free(str, FALSE);
+}
+
 int slirp_bind_outbound(struct socket *so, unsigned short af)
 {
     int ret = 0;
@@ -395,4 +437,4 @@ int slirp_bind_outbound(struct socket *so, unsigned short af)
         ret = bind(so->s, addr, addr_size);
     }
     return ret;
-}
\ No newline at end of file
+}
diff --git a/src/slirp.h b/src/slirp.h
index 4f8b133..80f6ac6 100644
--- a/src/slirp.h
+++ b/src/slirp.h
@@ -85,9 +85,9 @@ struct slirp_arphdr {
     /*
      *  Ethernet looks like this : This bit is variable sized however...
      */
-    unsigned char ar_sha[ETH_ALEN]; /* sender hardware address */
+    uint8_t ar_sha[ETH_ALEN]; /* sender hardware address */
     uint32_t ar_sip; /* sender IP address       */
-    unsigned char ar_tha[ETH_ALEN]; /* target hardware address */
+    uint8_t ar_tha[ETH_ALEN]; /* target hardware address */
     uint32_t ar_tip; /* target IP address       */
 } SLIRP_PACKED;
 
@@ -105,7 +105,7 @@ bool arp_table_search(Slirp *slirp, uint32_t ip_addr,
                       uint8_t out_ethaddr[ETH_ALEN]);
 
 struct ndpentry {
-    unsigned char eth_addr[ETH_ALEN]; /* sender hardware address */
+    uint8_t eth_addr[ETH_ALEN]; /* sender hardware address */
     struct in6_addr ip_addr; /* sender IP address       */
 };