sims/net/switch: move communicating and syncing ports to class

Aim is to introduce different types of ports.

sims/net/switch/net_switch.cc

@@ -47,6 +47,7 @@ extern "C" {
 
 static uint64_t sync_period = (500 * 1000ULL);  // 500ns
 static uint64_t eth_latency = (500 * 1000ULL);  // 500ns
+static int sync_mode = SIMBRICKS_PROTO_SYNC_SIMBRICKS;
 static pcap_dumper_t *dumpfile = nullptr;
 
 #ifdef NETSWITCH_STAT
@@ -66,9 +67,9 @@ static int stat_flag = 0;
 
 /* MAC address type */
 struct MAC {
-  const volatile uint8_t *data;
+  const uint8_t *data;
 
-  explicit MAC(const volatile uint8_t *data) : data(data) {
+  explicit MAC(const uint8_t *data) : data(data) {
   }
 
   bool operator==(const MAC &other) const {
@@ -93,12 +94,106 @@ struct hash<MAC> {
 };
 }  // namespace std
 
+class Port {
+ protected:
+  struct SimbricksNetIf netif_;
+  volatile union SimbricksProtoNetD2N *rx_;
+  int sync_;
+
+ public:
+  Port() : rx_(nullptr), sync_(0) {
+    memset(&netif_, 0, sizeof(netif_));
+  }
+
+  Port(const Port &other) : netif_(other.netif_), rx_(other.rx_),
+      sync_(other.sync_) {}
+
+  virtual ~Port() = default;
+
+  virtual bool Connect(const char *path, int sync) {
+    sync_ = sync;
+    return SimbricksNetIfInit(&netif_, path, &sync_) == 0;
+  }
+
+  virtual bool IsSync() {
+    return sync_;
+  }
+
+  virtual void Sync(uint64_t cur_ts) {
+    if (SimbricksNetIfN2DSync(&netif_, cur_ts, eth_latency, sync_period,
+                              sync_mode) != 0) {
+      fprintf(stderr, "SimbricksNetIfN2DSync failed\n");
+      abort();
+    }
+  }
+
+  virtual void AdvanceEpoch(uint64_t cur_ts) {
+    SimbricksNetIfAdvanceEpoch(cur_ts, sync_period, sync_mode);
+  }
+
+  virtual uint64_t NextTimestamp() {
+    return SimbricksNetIfD2NTimestamp(&netif_);
+  }
+
+  enum RxPollState {
+    kRxPollSuccess = 0,
+    kRxPollFail = 1,
+    kRxPollSync = 2,
+  };
+
+  virtual enum RxPollState RxPacket(
+      const void *& data, size_t &len, uint64_t cur_ts) {
+    assert(rx_ == nullptr);
+
+    rx_ = SimbricksNetIfD2NPoll(&netif_, cur_ts);
+    if (!rx_)
+      return kRxPollFail;
+
+    uint8_t type = rx_->dummy.own_type & SIMBRICKS_PROTO_NET_D2N_MSG_MASK;
+    if (type == SIMBRICKS_PROTO_NET_D2N_MSG_SEND) {
+      data = (const void *)rx_->send.data;
+      len = rx_->send.len;
+      return kRxPollSuccess;
+    } else if (type == SIMBRICKS_PROTO_NET_D2N_MSG_SYNC) {
+      return kRxPollSync;
+    } else {
+      fprintf(stderr, "switch_pkt: unsupported type=%u\n", type);
+      abort();
+    }
+  }
+
+  virtual void RxDone() {
+    assert(rx_ != nullptr);
+
+    SimbricksNetIfD2NDone(&netif_, rx_);
+    rx_ = nullptr;
+  }
+
+  virtual bool TxPacket(const void *data, size_t len, uint64_t cur_ts) {
+    volatile union SimbricksProtoNetN2D *msg_to =
+      SimbricksNetIfN2DAlloc(&netif_, cur_ts, eth_latency);
+    if (!msg_to)
+      return false;
+
+    volatile struct SimbricksProtoNetN2DRecv *rx;
+    rx = &msg_to->recv;
+    rx->len = len;
+    rx->port = 0;
+    memcpy((void *)rx->data, data, len);
+
+    // WMB();
+    rx->own_type =
+        SIMBRICKS_PROTO_NET_N2D_MSG_RECV | SIMBRICKS_PROTO_NET_N2D_OWN_DEV;
+    return true;
+  }
+};
+
 /* Global variables */
 static uint64_t cur_ts = 0;
 static int exiting = 0;
-static const volatile uint8_t bcast[6] = {0xFF};
+static const uint8_t bcast[6] = {0xFF};
 static const MAC bcast_addr(bcast);
-static std::vector<struct SimbricksNetIf> nsifs;
+static std::vector<Port> ports;
 static std::unordered_map<MAC, int> mac_table;
 
 static void sigint_handler(int dummy) {
@@ -115,28 +210,26 @@ static void sigusr2_handler(int dummy) {
 }
 #endif
 
-static void forward_pkt(volatile struct SimbricksProtoNetD2NSend *tx,
-                        size_t port) {
-  volatile union SimbricksProtoNetN2D *msg_to;
+static void forward_pkt(const void *pkt_data, size_t pkt_len, size_t port_id) {
   struct pcap_pkthdr ph;
-
+  Port &dest_port = ports[port_id];
 
   // log to pcap file if initialized
   if (dumpfile) {
       memset(&ph, 0, sizeof(ph));
       ph.ts.tv_sec = cur_ts / 1000000000000ULL;
       ph.ts.tv_usec = (cur_ts % 1000000000000ULL) / 1000ULL;
-      ph.caplen = tx->len;
-      ph.len = tx->len;
-      pcap_dump((unsigned char *)dumpfile, &ph, (unsigned char *)tx->data);
+      ph.caplen = pkt_len;
+      ph.len = pkt_len;
+      pcap_dump((unsigned char *)dumpfile, &ph, (unsigned char *)pkt_data);
   }
   // print sending tick: [packet type] source_IP -> dest_IP len:
-  
+
 #ifdef NETSWITCH_DEBUG
   uint16_t eth_proto;
   struct ethhdr *hdr;
   struct iphdr *iph;
-  hdr = (struct ethhdr*)tx->data; 
+  hdr = (struct ethhdr*)pkt_data;
   eth_proto = ntohs(hdr->h_proto);
   iph = (struct iphdr *)(hdr + 1);
   fprintf(stderr, "%20lu: ", cur_ts);
@@ -154,26 +247,14 @@ static void forward_pkt(volatile struct SimbricksProtoNetD2NSend *tx,
   fprintf(stderr, "%8X -> %8X len: %lu\n ", iph->saddr, iph->daddr, iph->tot_len + sizeof(struct ethhdr));
 #endif
 
-
-  msg_to = SimbricksNetIfN2DAlloc(&nsifs[port], cur_ts, eth_latency);
-  if (msg_to != NULL) {
-    volatile struct SimbricksProtoNetN2DRecv *rx;
-    rx = &msg_to->recv;
-    rx->len = tx->len;
-    rx->port = 0;
-    memcpy((void *)rx->data, (void *)tx->data, tx->len);
-
-    // WMB();
-    rx->own_type =
-        SIMBRICKS_PROTO_NET_N2D_MSG_RECV | SIMBRICKS_PROTO_NET_N2D_OWN_DEV;
-  } else {
-    fprintf(stderr, "forward_pkt: dropping packet\n");
-  }
+  if (!dest_port.TxPacket(pkt_data, pkt_len, cur_ts))
+    fprintf(stderr, "forward_pkt: dropping packet on port %zu\n", port_id);
 }
 
-static void switch_pkt(struct SimbricksNetIf *nsif, size_t iport) {
-  volatile union SimbricksProtoNetD2N *msg_from =
-      SimbricksNetIfD2NPoll(nsif, cur_ts);
+static void switch_pkt(Port &port, size_t iport) {
+  const void *pkt_data;
+  size_t pkt_len;
+
 #ifdef NETSWITCH_STAT
   d2n_poll_total += 1;
   if (stat_flag){
@@ -181,7 +262,8 @@ static void switch_pkt(struct SimbricksNetIf *nsif, size_t iport) {
   }
 #endif
 
-  if (msg_from == NULL) {
+  enum Port::RxPollState poll = port.RxPacket(pkt_data, pkt_len, cur_ts);
+  if (poll == Port::kRxPollFail) {
     return;
   }
 
@@ -192,12 +274,9 @@ static void switch_pkt(struct SimbricksNetIf *nsif, size_t iport) {
   }
 #endif
 
-  uint8_t type = msg_from->dummy.own_type & SIMBRICKS_PROTO_NET_D2N_MSG_MASK;
-  if (type == SIMBRICKS_PROTO_NET_D2N_MSG_SEND) {
-    volatile struct SimbricksProtoNetD2NSend *tx;
-    tx = &msg_from->send;
+  if (poll == Port::kRxPollSuccess) {
     // Get MAC addresses
-    MAC dst(tx->data), src(tx->data + 6);
+    MAC dst((const uint8_t *)pkt_data), src((const uint8_t *)pkt_data + 6);
     // MAC learning
     if (!(src == bcast_addr)) {
       mac_table[src] = iport;
@@ -205,17 +284,17 @@ static void switch_pkt(struct SimbricksNetIf *nsif, size_t iport) {
     // L2 forwarding
     if (mac_table.count(dst) > 0) {
       size_t eport = mac_table.at(dst);
-      forward_pkt(tx, eport);
+      forward_pkt(pkt_data, pkt_len, eport);
     } else {
       // Broadcast
-      for (size_t eport = 0; eport < nsifs.size(); eport++) {
+      for (size_t eport = 0; eport < ports.size(); eport++) {
         if (eport != iport) {
           // Do not forward to ingress port
-          forward_pkt(tx, eport);
+          forward_pkt(pkt_data, pkt_len, eport);
         }
       }
     }
-  } else if (type == SIMBRICKS_PROTO_NET_D2N_MSG_SYNC) {
+  } else if (poll == Port::kRxPollSync) {
 #ifdef NETSWITCH_STAT
     d2n_poll_sync += 1;
     if (stat_flag){
@@ -223,31 +302,29 @@ static void switch_pkt(struct SimbricksNetIf *nsif, size_t iport) {
     }
 #endif
   } else {
-    fprintf(stderr, "switch_pkt: unsupported type=%u\n", type);
+    fprintf(stderr, "switch_pkt: unsupported poll result=%u\n", poll);
     abort();
   }
-  SimbricksNetIfD2NDone(nsif, msg_from);
+  port.RxDone();
 }
 
 int main(int argc, char *argv[]) {
   int c;
   int bad_option = 0;
   int sync_eth = 1;
-  int sync_mode = SIMBRICKS_PROTO_SYNC_SIMBRICKS;
   pcap_t *pc = nullptr;
 
   // Parse command line argument
   while ((c = getopt(argc, argv, "s:uS:E:m:p:")) != -1 && !bad_option) {
     switch (c) {
       case 's': {
-        struct SimbricksNetIf nsif;
-        int sync = sync_eth;
+        Port port;
         fprintf(stderr, "Switch connecting to: %s\n", optarg);
-        if (SimbricksNetIfInit(&nsif, optarg, &sync) != 0) {
+        if (!port.Connect(optarg, sync_eth)) {
           fprintf(stderr, "connecting to %s failed\n", optarg);
           return EXIT_FAILURE;
         }
-        nsifs.push_back(nsif);
+        ports.push_back(port);
         break;
       }
 
@@ -287,7 +364,7 @@ int main(int argc, char *argv[]) {
     }
   }
 
-  if (nsifs.empty() || bad_option) {
+  if (ports.empty() || bad_option) {
     fprintf(stderr,
             "Usage: net_switch [-S SYNC-PERIOD] [-E ETH-LATENCY] "
             "-s SOCKET-A [-s SOCKET-B ...]\n");
@@ -306,24 +383,20 @@ int main(int argc, char *argv[]) {
   printf("start polling\n");
   while (!exiting) {
     // Sync all interfaces
-    for (auto &nsif : nsifs) {
-      if (SimbricksNetIfN2DSync(&nsif, cur_ts, eth_latency, sync_period,
-                                sync_mode) != 0) {
-        fprintf(stderr, "SimbricksNetIfN2DSync failed\n");
-        abort();
-      }
-    }
-    SimbricksNetIfAdvanceEpoch(cur_ts, sync_period, sync_mode);
+    for (auto &port : ports)
+      port.Sync(cur_ts);
+    for (auto &port : ports)
+      port.AdvanceEpoch(cur_ts);
 
     // Switch packets
     uint64_t min_ts;
     do {
       min_ts = ULLONG_MAX;
-      for (size_t port = 0; port < nsifs.size(); port++) {
-        auto &nsif = nsifs.at(port);
-        switch_pkt(&nsif, port);
-        if (nsif.sync) {
-          uint64_t ts = SimbricksNetIfD2NTimestamp(&nsif);
+      for (size_t port_i = 0; port_i < ports.size(); port_i++) {
+        auto &port = ports.at(port_i);
+        switch_pkt(port, port_i);
+        if (port.IsSync()) {
+          uint64_t ts = port.NextTimestamp();
           min_ts = ts < min_ts ? ts : min_ts;
         }
       }
@@ -331,6 +404,7 @@ int main(int argc, char *argv[]) {
 
     // Update cur_ts
     if (min_ts < ULLONG_MAX) {
+      // a bit broken but should probably do
       cur_ts = SimbricksNetIfAdvanceTime(min_ts, sync_period, sync_mode);
     }
   }