Network detect (#26)

src/modules/network.cpp

@@ -1,34 +1,272 @@
 #include "modules/network.hpp"
 
-#include <iostream>
-
 waybar::modules::Network::Network(Json::Value config)
-  : config_(std::move(config)),
-    ifid_(if_nametoindex(config_["interface"].asCString())),
+  : config_(std::move(config)), family_(AF_INET),
     signal_strength_dbm_(0), signal_strength_(0)
 {
-  if (ifid_ == 0) {
-    throw std::runtime_error("Can't found network interface");
+  sock_fd_ = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+  if (sock_fd_ < 0) {
+    throw std::runtime_error("Can't open network socket");
+  }
+  nladdr_.nl_family = AF_NETLINK;
+  nladdr_.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR;
+  if (bind(sock_fd_, reinterpret_cast<struct sockaddr *>(&nladdr_),
+    sizeof(nladdr_)) != 0) {
+    throw std::runtime_error("Can't bind network socket");
+  }
+  if (config_["interface"]) {
+    ifid_ = if_nametoindex(config_["interface"].asCString());
+    ifname_ = config_["interface"].asString();
+    if (ifid_ <= 0) {
+      throw std::runtime_error("Can't found network interface");
+    }
+  } else {
+    ifid_ = getExternalInterface();
+    if (ifid_ > 0) {
+      char ifname[IF_NAMESIZE];
+      if_indextoname(ifid_, ifname);
+      ifname_ = ifname;
+    }
   }
   label_.set_name("network");
-  uint32_t interval = config_["interval"] ? config_["inveral"].asUInt() : 30;
-  thread_ = [this, interval] {
-    getInfo();
-    Glib::signal_idle().connect_once(sigc::mem_fun(*this, &Network::update));
-    thread_.sleep_for(chrono::seconds(interval));
+  getInfo();
+  Glib::signal_idle().connect_once(sigc::mem_fun(*this, &Network::update));
+  thread_ = [this] {
+    char buf[4096];
+    uint64_t len = netlinkResponse(sock_fd_, buf, sizeof(buf),
+      RTMGRP_LINK | RTMGRP_IPV4_IFADDR);
+    bool need_update = false;
+    for (auto nh = reinterpret_cast<struct nlmsghdr *>(buf); NLMSG_OK(nh, len);
+      nh = NLMSG_NEXT(nh, len)) {
+      if (nh->nlmsg_type == NLMSG_DONE) {
+        break;
+      }
+      if (nh->nlmsg_type == NLMSG_ERROR) {
+        continue;
+      }
+      if (nh->nlmsg_type < RTM_NEWADDR) {
+        auto rtif = static_cast<struct ifinfomsg *>(NLMSG_DATA(nh));
+        if (rtif->ifi_index == static_cast<int>(ifid_)) {
+          need_update = true;
+          if (!(rtif->ifi_flags & IFF_RUNNING)) {
+            disconnected();
+          }
+        }
+      }
+    }
+    if (ifid_ <= 0 && !config_["interface"]) {
+      // Need to wait before get external interface
+      thread_.sleep_for(std::chrono::seconds(1));
+      ifid_ = getExternalInterface();
+      if (ifid_ > 0) {
+        char ifname[IF_NAMESIZE];
+        if_indextoname(ifid_, ifname);
+        ifname_ = ifname;
+        need_update = true;
+      }
+    }
+    if (need_update) {
+      getInfo();
+      Glib::signal_idle().connect_once(sigc::mem_fun(*this, &Network::update));
+    }
   };
 };
 
 auto waybar::modules::Network::update() -> void
 {
-  auto format = config_["format"] ? config_["format"].asString() : "{essid}";
+  auto format = config_["format"] ? config_["format"].asString() : "{ifname}";
+  if (ifid_ <= 0) {
+    format = config_["format-disconnected"]
+      ? config_["format-disconnected"].asString() : format;
+    label_.get_style_context()->add_class("disconnected");
+  } else {
+    if (essid_.empty()) {
+      format = config_["format-ethernet"]
+        ? config_["format-ethernet"].asString() : format;
+    } else {
+      format = config_["format-wifi"]
+        ? config_["format-wifi"].asString() : format;
+    }
+    label_.get_style_context()->remove_class("disconnected");
+  }
   label_.set_text(fmt::format(format,
     fmt::arg("essid", essid_),
     fmt::arg("signaldBm", signal_strength_dbm_),
-    fmt::arg("signalStrength", signal_strength_)
+    fmt::arg("signalStrength", signal_strength_),
+    fmt::arg("ifname", ifname_)
   ));
 }
 
+void waybar::modules::Network::disconnected()
+{
+  essid_.clear();
+  signal_strength_dbm_ = 0;
+  signal_strength_ = 0;
+  ifname_.clear();
+  ifid_ = -1;
+}
+
+// Based on https://gist.github.com/Yawning/c70d804d4b8ae78cc698
+int waybar::modules::Network::getExternalInterface()
+{
+  struct nlmsghdr *hdr = nullptr;
+  struct rtmsg *rt = nullptr;
+  void *resp = nullptr;
+  int ifidx = -1;
+
+  /* Allocate space for the request. */
+  uint32_t reqlen = NLMSG_SPACE(sizeof(*rt));
+  void *req = nullptr;
+  if ((req = calloc(1, reqlen)) == nullptr) {
+    goto out; /* ENOBUFS */
+  }
+
+  /* Build the RTM_GETROUTE request. */
+  hdr = static_cast<struct nlmsghdr *>(req);
+  hdr->nlmsg_len = NLMSG_LENGTH(sizeof(*rt));
+  hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
+  hdr->nlmsg_type = RTM_GETROUTE;
+  rt = static_cast<struct rtmsg *>(NLMSG_DATA(hdr));
+  rt->rtm_family = family_;
+  rt->rtm_table = RT_TABLE_MAIN;
+
+  /* Issue the query. */
+  if (netlinkRequest(sock_fd_, req, reqlen) < 0) {
+    goto out;
+  }
+
+  /* Allocate space for the response. */
+  static const uint32_t route_buffer_size = 8192;
+  if ((resp = calloc(1, route_buffer_size)) == nullptr) {
+    goto out; /* ENOBUFS */
+  }
+
+  /* Read the response(s).
+   *
+   * WARNING: All the packets generated by the request must be consumed (as in,
+   * consume responses till NLMSG_DONE/NLMSG_ERROR is encountered).
+   */
+  do {
+    uint64_t len = netlinkResponse(sock_fd_, resp, route_buffer_size);
+    if (len < 0) {
+      goto out;
+    }
+
+    /* Parse the response payload into netlink messages. */
+    for (hdr = static_cast<struct nlmsghdr *>(resp); NLMSG_OK(hdr, len);
+      hdr = NLMSG_NEXT(hdr, len)) {
+      if (hdr->nlmsg_type == NLMSG_DONE) {
+        goto out;
+      }
+      if (hdr->nlmsg_type == NLMSG_ERROR) {
+        /* Even if we found the interface index, something is broken with the
+         * netlink socket, so return an error.
+         */
+        ifidx = -1;
+        goto out;
+      }
+
+      /* If we found the correct answer, skip parsing the attributes. */
+      if (ifidx != -1) {
+        continue;
+      }
+
+      /* Find the message(s) concerting the main routing table, each message
+       * corresponds to a single routing table entry.
+       */
+      rt = static_cast<struct rtmsg *>(NLMSG_DATA(hdr));
+      if (rt->rtm_table != RT_TABLE_MAIN) {
+        continue;
+      }
+
+      /* Parse all the attributes for a single routing table entry. */
+      struct rtattr *attr = RTM_RTA(rt);
+      uint64_t attrlen = RTM_PAYLOAD(hdr);
+      bool has_gateway = false;
+      bool has_destination = false;
+      int temp_idx = -1;
+      for (; RTA_OK(attr, attrlen); attr = RTA_NEXT(attr, attrlen)) {
+        /* Determine if this routing table entry corresponds to the default
+         * route by seeing if it has a gateway, and if a destination addr is
+         * set, that it is all 0s.
+         */
+        switch (attr->rta_type) {
+          case RTA_GATEWAY:
+            /* The gateway of the route.
+             *
+             * If someone every needs to figure out the gateway address as well,
+             * it's here as the attribute payload.
+             */
+            has_gateway = true;
+            break;
+          case RTA_DST: {
+            /* The destination address.
+             * Should be either missing, or maybe all 0s.  Accept both.
+             */
+            const uint32_t nr_zeroes = (family_ == AF_INET) ? 4 : 16;
+            unsigned char c = 0;
+            size_t dstlen = RTA_PAYLOAD(attr);
+            if (dstlen != nr_zeroes) {
+              break;
+            }
+            for (uint32_t i = 0; i < dstlen; i += 1) {
+              c |= *(unsigned char *)(RTA_DATA(attr) + i);
+            }
+            has_destination = (c == 0);
+            break;
+          }
+          case RTA_OIF:
+            /* The output interface index. */
+            temp_idx = *static_cast<int*>(RTA_DATA(attr));
+            break;
+          default:
+            break;
+        }
+      }
+      /* If this is the default route, and we know the interface index,
+       * we can stop parsing this message.
+       */
+      if (has_gateway && !has_destination && temp_idx != -1) {
+        ifidx = temp_idx;
+        break;
+      }
+    }
+  } while (true);
+
+out:
+  if (req)
+    free(req);
+  if (resp)
+    free(resp);
+  return ifidx;
+}
+
+uint64_t waybar::modules::Network::netlinkRequest(int fd, void *req,
+  uint32_t reqlen, uint32_t groups)
+{
+  struct sockaddr_nl sa = {0};
+  sa.nl_family = AF_NETLINK;
+  sa.nl_groups = groups;
+  struct iovec iov = { req, reqlen };
+  struct msghdr msg = { &sa, sizeof(sa), &iov, 1, nullptr, 0, 0 };
+  return sendmsg(fd, &msg, 0);
+}
+
+uint64_t waybar::modules::Network::netlinkResponse(int fd, void *resp,
+  uint32_t resplen, uint32_t groups)
+{
+  uint64_t ret;
+  struct sockaddr_nl sa = {0};
+  sa.nl_family = AF_NETLINK;
+  sa.nl_groups = groups;
+  struct iovec iov = { resp, resplen };
+  struct msghdr msg = { &sa, sizeof(sa), &iov, 1, nullptr, 0, 0 };
+  ret = recvmsg(fd, &msg, 0);
+  if (msg.msg_flags & MSG_TRUNC)
+    return -1;
+  return ret;
+}
+
 int waybar::modules::Network::scanCb(struct nl_msg *msg, void *data) {
     auto net = static_cast<waybar::modules::Network *>(data);
     auto gnlh = static_cast<genlmsghdr *>(nlmsg_data(nlmsg_hdr(msg)));