Add class VpnPeer

Makefile

@@ -2,7 +2,7 @@ CXX=g++
 CXXFLAGS=-O2 -g -Wall -Wextra -std=c++17
 CXXLIBS=
 
-OBJS=UdpVpn.o TunDevice.o util.o main.o
+OBJS=UdpVpn.o VpnPeer.o TunDevice.o util.o main.o
 TARGET=congestvpn
 
 all: $(TARGET)

VpnPeer.cpp

@@ -0,0 +1,23 @@
+#include "VpnPeer.hpp"
+#include "UdpVpn.hpp"
+
+#include <cstdint>
+#include <cstring>
+#include <functional>
+
+VpnPeer::VpnPeer(UdpVpn* vpn, const sockaddr_in6& ext_addr,
+        const in6_addr int_addr)
+    : _vpn(vpn), _ext_addr(ext_addr), _int_addr(int_addr)
+{}
+
+
+size_t VpnPeer::write(const char* data, size_t len) {
+    ssize_t nsent;
+
+    nsent = sendto(_vpn->get_socket_fd(), data, len, MSG_CONFIRM,
+            (const struct sockaddr*) &_ext_addr, sizeof(_ext_addr));
+    if(nsent < 0)
+        throw NetError("Could not send UDP packet", errno, true);
+
+    return (size_t) nsent;
+}

VpnPeer.hpp

@@ -0,0 +1,33 @@
+#pragma once
+
+/** A peer of a bound (server) instance of UdpVpn */
+
+#include <netinet/in.h>
+#include "util.hpp"
+
+class UdpVpn;
+
+class VpnPeer {
+    public:
+        class NetError : public MsgException {
+            public:
+                NetError(
+                        const std::string& msg,
+                        int code=0,
+                        bool is_perror=false)
+                    : MsgException(msg, code, is_perror) {}
+        };
+
+        VpnPeer(UdpVpn* vpn, const sockaddr_in6& ext_addr,
+                const in6_addr int_addr);
+
+        const sockaddr_in6& get_ext_addr() const { return _ext_addr; }
+        const in6_addr& get_int_addr() const { return _int_addr; }
+
+        size_t write(const char* data, size_t len);
+
+    private:
+        UdpVpn* _vpn;
+        sockaddr_in6 _ext_addr;
+        in6_addr _int_addr;
+};