snmp: turn the "try next OID" code block into a macro to avoid errors

diff --git a/src/agent.c b/src/agent.c
index b26de384421ec816d4929a63504b1cb54e4a8d69..eb3da9dd4d4c7b349f3169fcc2919fe349b9675c 100644 (file)
--- a/src/agent.c
+++ b/src/agent.c
@@ -737,6 +737,19 @@ header_tprpiindexed_table(struct variable *vp, oid *name, size_t *length,
 #define LLDP_SNMP_MED_POE_PD_POWERSOURCE 23
 #define LLDP_SNMP_MED_POE_PD_POWERPRIORITY 24
 
+/* The following macro should be used anytime where the selected OID
+   is finally not returned (for example, when the associated data is
+   not available). In this case, we retry the function with the next
+   OID. */
+#define TRYNEXT(X)                                                     \
+       do {                                                            \
+               if (!exact && (name[*length-1] < MAX_SUBID))            \
+                       return X(vp, name, length,                      \
+                                exact, var_len, write_method);         \
+               return NULL;                                            \
+       } while (0)
+
+
 static u_char*
 agent_h_scalars(struct variable *vp, oid *name, size_t *length,
     int exact, size_t *var_len, WriteMethod **write_method)
@@ -798,11 +811,12 @@ agent_h_scalars(struct variable *vp, oid *name, size_t *length,
                return (u_char *)&long_ret;
        default:
                break;
-        }
-        return NULL;
+       }
+       return NULL;
 }
 
 #ifdef ENABLE_LLDPMED
+/* This one is an helper function. */
 static unsigned long
 agent_h_med_power(struct variable *vp, struct lldpd_med_power *power)
 {
@@ -966,12 +980,7 @@ agent_h_local_med(struct variable *vp, oid *name, size_t *length,
        default:
                return NULL;
        }
-       /* At this point, we seem to have hit an inventory variable that is not
-        * available, try to get the next one */
-       if (name[*length-1] < MAX_SUBID)
-               return agent_h_local_med(vp, name, length,
-                   exact, var_len, write_method);
-       return NULL;
+       TRYNEXT(agent_h_local_med);
 }
 
 static u_char*
@@ -1043,11 +1052,7 @@ agent_h_local_med_power(struct variable *vp, oid *name, size_t *length,
                return (u_char *)&long_ret;
 
 localpower_failed:
-       /* No valid data was found, we should try the next one! */
-       if (!exact && (name[*length-1] < MAX_SUBID))
-               return agent_h_local_med_power(vp, name, length,
-                   exact, var_len, write_method);
-        return NULL;
+       TRYNEXT(agent_h_local_med_power);
 }
 
 static u_char*
@@ -1062,6 +1067,7 @@ agent_h_remote_med(struct variable *vp, oid *name, size_t *length,
                    exact, var_len, write_method, TPR_VARIANT_NONE)) == NULL)
                return NULL;
 
+       /* Optimization, we need to skip the whole chassis if no MED is available */
        if (!port->p_chassis->c_med_cap_available) {
                if (!exact && (name[*length-2] < MAX_SUBID))
                        name[*length-2]++;
@@ -1122,11 +1128,7 @@ agent_h_remote_med(struct variable *vp, oid *name, size_t *length,
                return NULL;
         }
 remotemed_failed:
-       /* No valid data was found, we should try the next one! */
-       if (!exact && (name[*length-1] < MAX_SUBID))
-               return agent_h_remote_med(vp, name, length,
-                   exact, var_len, write_method);
-        return NULL;
+       TRYNEXT(agent_h_remote_med);
 }
 
 static u_char*
@@ -1142,6 +1144,7 @@ agent_h_remote_med_policy(struct variable *vp, oid *name, size_t *length,
                    exact, var_len, write_method, TPR_VARIANT_MED_POLICY)) == NULL)
                return NULL;
 
+       /* Optimization, we need to skip the whole chassis if no MED is available */
        if (!port->p_chassis->c_med_cap_available) {
                if (!exact && (name[*length-2] < MAX_SUBID))
                        name[*length-2]++;
@@ -1175,11 +1178,7 @@ agent_h_remote_med_policy(struct variable *vp, oid *name, size_t *length,
                return NULL;
         }
 remotemedpolicy_failed:
-       /* No valid data was found, we should try the next one! */
-       if (!exact && (name[*length-1] < MAX_SUBID))
-               return agent_h_remote_med_policy(vp, name, length,
-                   exact, var_len, write_method);
-       return NULL;
+       TRYNEXT(agent_h_remote_med_policy);
 }
 
 static u_char*
@@ -1194,6 +1193,7 @@ agent_h_remote_med_location(struct variable *vp, oid *name, size_t *length,
                    exact, var_len, write_method, TPR_VARIANT_MED_LOCATION)) == NULL)
                return NULL;
 
+       /* Optimization, we need to skip the whole chassis if no MED is available */
        if (!port->p_chassis->c_med_cap_available) {
                if (!exact && (name[*length-2] < MAX_SUBID))
                        name[*length-2]++;
@@ -1215,11 +1215,7 @@ agent_h_remote_med_location(struct variable *vp, oid *name, size_t *length,
                return NULL;
         }
 remotemedlocation_failed:
-       /* No valid data was found, we should try the next one! */
-       if (!exact && (name[*length-1] < MAX_SUBID))
-               return agent_h_remote_med_location(vp, name, length,
-                   exact, var_len, write_method);
-       return NULL;
+       TRYNEXT(agent_h_remote_med_location);
 }
 #endif
 
@@ -1257,7 +1253,7 @@ agent_h_local_chassis(struct variable *vp, oid *name, size_t *length,
        default:
                break;
         }
-        return NULL;
+       return NULL;
 }
 
 static u_char*
@@ -1432,10 +1428,7 @@ agent_h_local_port(struct variable *vp, oid *name, size_t *length,
        default:
                break;
         }
-       if (!exact && (name[*length-1] < MAX_SUBID))
-               return agent_h_local_port(vp, name, length,
-                   exact, var_len, write_method);
-       return NULL;
+       TRYNEXT(agent_h_local_port);
 }
 
 #ifdef ENABLE_DOT1
@@ -1729,10 +1722,7 @@ agent_h_remote_port(struct variable *vp, oid *name, size_t *length,
        default:
                break;
         }
-       if (!exact && (name[*length-1] < MAX_SUBID))
-               return agent_h_remote_port(vp, name, length,
-                   exact, var_len, write_method);
-       return NULL;
+       TRYNEXT(agent_h_remote_port);
 }
 
 static u_char*