Improve log_dhcp to always tell from which server a message came.

Currently this information is derived from the DHO_SERVERID option.
But when the server doesn't set it, no source info is logged. Print
the src ip of the udp packet as "from" in this case. This is not perfect
as there could be a dhcp forwarder involved, but this is better than nothing.

Thanks to Gerd von Egidy.

diff --git a/dhcpcd.c b/dhcpcd.c
index 983c3b64695f3c12bc01efacdc6f5d9a31a75f53..bc23934080af69bf6d15535398595d0ca259a1bc 100644 (file)
--- a/dhcpcd.c
+++ b/dhcpcd.c
@@ -407,7 +407,7 @@ start_expire(void *arg)
 
 static void
 log_dhcp(int lvl, const char *msg,
-    const struct interface *iface, const struct dhcp_message *dhcp)
+    const struct interface *iface, const struct dhcp_message *dhcp, const struct in_addr *from)
 {
        char *a;
        struct in_addr addr;
@@ -432,9 +432,9 @@ log_dhcp(int lvl, const char *msg,
                        syslog(lvl, "%s: %s %s from %s",
                            iface->name, msg, a, inet_ntoa(addr));
        } else if (a != NULL)
-               syslog(lvl, "%s: %s %s", iface->name, msg, a);
+               syslog(lvl, "%s: %s %s from %s", iface->name, msg, a, inet_ntoa(*from));
        else
-               syslog(lvl, "%s: %s", iface->name, msg);
+               syslog(lvl, "%s: %s from %s", iface->name, msg, inet_ntoa(*from));
        free(a);
 }
 
@@ -463,7 +463,7 @@ whitelisted_ip(const struct if_options *ifo, in_addr_t addr)
 }
 
 static void
-handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp)
+handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp, const struct in_addr *from)
 {
        struct if_state *state = iface->state;
        struct if_options *ifo = state->options;
@@ -485,11 +485,11 @@ handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp)
                if (has_option_mask(ifo->requiremask, DHO_SERVERID) &&
                    get_option_addr(&addr, dhcp, DHO_SERVERID) == -1)
                {
-                       log_dhcp(LOG_WARNING, "reject NAK", iface, dhcp);
+                       log_dhcp(LOG_WARNING, "reject NAK", iface, dhcp, from);
                        return;
                }
                /* We should restart on a NAK */
-               log_dhcp(LOG_WARNING, "NAK:", iface, dhcp);
+               log_dhcp(LOG_WARNING, "NAK:", iface, dhcp, from);
                if (!(options & DHCPCD_TEST)) {
                        drop_config(iface, "NAK");
                        unlink(iface->leasefile);
@@ -512,7 +512,7 @@ handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp)
                         * To ignore bootp, require dhcp_message_type instead. */
                        if (type == 0 && i == DHO_SERVERID)
                                continue;
-                       log_dhcp(LOG_WARNING, "reject DHCP", iface, dhcp);
+                       log_dhcp(LOG_WARNING, "reject DHCP", iface, dhcp, from);
                        return;
                }
        }               
@@ -529,7 +529,7 @@ handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp)
                if (type == 0 ||
                    get_option_addr(&lease->server, dhcp, DHO_SERVERID) != 0)
                        lease->server.s_addr = INADDR_ANY;
-               log_dhcp(LOG_INFO, "offered", iface, dhcp);
+               log_dhcp(LOG_INFO, "offered", iface, dhcp, from);
                free(state->offer);
                state->offer = dhcp;
                *dhcpp = NULL;
@@ -558,18 +558,18 @@ handle_dhcp(struct interface *iface, struct dhcp_message **dhcpp)
 
        if (type) {
                if (type == DHCP_OFFER) {
-                       log_dhcp(LOG_INFO, "ignoring offer of", iface, dhcp);
+                       log_dhcp(LOG_INFO, "ignoring offer of", iface, dhcp, from);
                        return;
                }
 
                /* We should only be dealing with acks */
                if (type != DHCP_ACK) {
-                       log_dhcp(LOG_ERR, "not ACK or OFFER", iface, dhcp);
+                       log_dhcp(LOG_ERR, "not ACK or OFFER", iface, dhcp, from);
                        return;
                }
 
                if (!(ifo->options & DHCPCD_INFORM))
-                       log_dhcp(LOG_INFO, "acknowledged", iface, dhcp);
+                       log_dhcp(LOG_INFO, "acknowledged", iface, dhcp, from);
        }
 
        /* BOOTP could have already assigned this above, so check we still
@@ -685,7 +685,7 @@ handle_dhcp_packet(void *arg)
                            hwaddr_ntoa(dhcp->chaddr, sizeof(dhcp->chaddr)));
                        continue;
                }
-               handle_dhcp(iface, &dhcp);
+               handle_dhcp(iface, &dhcp, &from);
                if (iface->raw_fd == -1)
                        break;
        }