ipdpd: Pass MPL to application at flow_allocation

The maximum packet lifetime (MPL) is a property of the flow that needs
to be passed to the reliable transmission protocol (FRCP) for its
correct operation. Previously, the value of MPL was set fixed as one
of the (fixed) Delta-t parameters. This patch makes the MPL a property
of the layer, and it can now be set per layer-type at build time.
This is a step towards a proper MPL estimator in the flow allocator.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

2 files changed, 7 insertions, 2 deletions

diff --git a/src/ipcpd/udp/CMakeLists.txt b/src/ipcpd/udp/CMakeLists.txt
index f1a29ef6..8ae5518e 100644
--- a/src/ipcpd/udp/CMakeLists.txt
+++ b/src/ipcpd/udp/CMakeLists.txt
@@ -58,6 +58,8 @@ set(IPCP_UDP_RD_THR 3 CACHE STRING
   "Number of reader threads in UDP IPCP")
 set(IPCP_UDP_WR_THR 3 CACHE STRING
   "Number of writer threads in UDP IPCP")
+set(IPCP_UDP_MPL 60 CACHE STRING
+    "Default maximum packet lifetime for the UDP IPCP, in seconds")
 
 include(AddCompileFlags)
 if (CMAKE_BUILD_TYPE MATCHES "Debug*")
diff --git a/src/ipcpd/udp/main.c b/src/ipcpd/udp/main.c
index 5c57e6b8..3b354ceb 100644
--- a/src/ipcpd/udp/main.c
+++ b/src/ipcpd/udp/main.c
@@ -279,6 +279,7 @@ static int ipcp_udp_port_req(struct sockaddr_in * c_saddr,
         struct timespec    ts        = {0, FD_UPDATE_TIMEOUT * 1000};
         struct timespec    abstime;
         int                fd;
+        time_t             mpl = IPCP_UDP_MPL;
 
         clock_gettime(PTHREAD_COND_CLOCK, &abstime);
 
@@ -297,7 +298,7 @@ static int ipcp_udp_port_req(struct sockaddr_in * c_saddr,
         }
 
         /* reply to IRM */
-        fd = ipcp_flow_req_arr(dst, ipcp_dir_hash_len(), qs, data, len);
+        fd = ipcp_flow_req_arr(dst, ipcp_dir_hash_len(), qs, mpl, data, len);
         if (fd < 0) {
                 pthread_mutex_unlock(&ipcpi.alloc_lock);
                 log_err("Could not get new flow from IRMd.");
@@ -329,6 +330,8 @@ static int ipcp_udp_port_alloc_reply(const struct sockaddr_in * saddr,
                                      const void *               data,
                                      size_t                     len)
 {
+        time_t mpl = IPCP_UDP_MPL;
+
         pthread_rwlock_wrlock(&udp_data.flows_lock);
 
         if (memcmp(&udp_data.fd_to_uf[s_eid].r_saddr, saddr, sizeof(*saddr))) {
@@ -343,7 +346,7 @@ static int ipcp_udp_port_alloc_reply(const struct sockaddr_in * saddr,
 
         pthread_rwlock_unlock(&udp_data.flows_lock);
 
-        if (ipcp_flow_alloc_reply(s_eid, response, data, len) < 0) {
+        if (ipcp_flow_alloc_reply(s_eid, response, mpl, data, len) < 0) {
                 log_dbg("Failed to reply to flow allocation.");
                 return -1;
         }