diff --git a/internal/sys.cpp b/internal/sys.cpp
index db843ac..b4a1ffc 100644
--- a/internal/sys.cpp
+++ b/internal/sys.cpp
@@ -19,6 +19,7 @@
 #include <fcntl.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
+#include <sys/sendfile.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ -92,6 +93,35 @@
     return ::poll(fds, nfds, timeout);
 }
 
+int SysImpl::socket(int domain, int type, int protocol) const
+{
+    return ::socket(domain, type, protocol);
+}
+
+int SysImpl::connect(int sockfd, const struct sockaddr* addr,
+                     socklen_t addrlen) const
+{
+    return ::connect(sockfd, addr, addrlen);
+}
+
+ssize_t SysImpl::sendfile(int out_fd, int in_fd, off_t* offset,
+                          size_t count) const
+{
+    return ::sendfile(out_fd, in_fd, offset, count);
+}
+
+int SysImpl::getaddrinfo(const char* node, const char* service,
+                         const struct addrinfo* hints,
+                         struct addrinfo** res) const
+{
+    return ::getaddrinfo(node, service, hints, res);
+}
+
+void SysImpl::freeaddrinfo(struct addrinfo* res) const
+{
+    ::freeaddrinfo(res);
+}
+
 SysImpl sys_impl;
 
 } // namespace internal
diff --git a/internal/sys.hpp b/internal/sys.hpp
index 41fb46b..a399903 100644
--- a/internal/sys.hpp
+++ b/internal/sys.hpp
@@ -7,8 +7,11 @@
  * other pieces.
  */
 
+#include <netdb.h>
 #include <poll.h>
 #include <sys/mman.h>
+#include <sys/socket.h>
+#include <sys/types.h>
 
 #include <cinttypes>
 #include <cstddef>
@@ -39,6 +42,15 @@
     virtual int getpagesize() const = 0;
     virtual int ioctl(int fd, unsigned long request, void* param) const = 0;
     virtual int poll(struct pollfd* fds, nfds_t nfds, int timeout) const = 0;
+    virtual int socket(int domain, int type, int protocol) const = 0;
+    virtual int connect(int sockfd, const struct sockaddr* addr,
+                        socklen_t addrlen) const = 0;
+    virtual ssize_t sendfile(int out_fd, int in_fd, off_t* offset,
+                             size_t count) const = 0;
+    virtual int getaddrinfo(const char* node, const char* service,
+                            const struct addrinfo* hints,
+                            struct addrinfo** res) const = 0;
+    virtual void freeaddrinfo(struct addrinfo* res) const = 0;
     virtual std::int64_t getSize(const char* pathname) const = 0;
 };
 
@@ -63,6 +75,15 @@
     int getpagesize() const override;
     int ioctl(int fd, unsigned long request, void* param) const override;
     int poll(struct pollfd* fds, nfds_t nfds, int timeout) const override;
+    int socket(int domain, int type, int protocol) const override;
+    int connect(int sockfd, const struct sockaddr* addr,
+                socklen_t addrlen) const override;
+    ssize_t sendfile(int out_fd, int in_fd, off_t* offset,
+                     size_t count) const override;
+    int getaddrinfo(const char* node, const char* service,
+                    const struct addrinfo* hints,
+                    struct addrinfo** res) const override;
+    void freeaddrinfo(struct addrinfo* res) const override;
     /* returns 0 on failure, or if the file is zero bytes. */
     std::int64_t getSize(const char* pathname) const override;
 };
diff --git a/tools/test/internal_sys_mock.hpp b/tools/test/internal_sys_mock.hpp
index ce37d91..97f95bf 100644
--- a/tools/test/internal_sys_mock.hpp
+++ b/tools/test/internal_sys_mock.hpp
@@ -26,6 +26,13 @@
     MOCK_CONST_METHOD0(getpagesize, int());
     MOCK_CONST_METHOD3(ioctl, int(int, unsigned long, void*));
     MOCK_CONST_METHOD3(poll, int(struct pollfd*, nfds_t, int));
+    MOCK_CONST_METHOD3(socket, int(int, int, int));
+    MOCK_CONST_METHOD3(connect, int(int, const struct sockaddr*, socklen_t));
+    MOCK_CONST_METHOD4(sendfile, ssize_t(int, int, off_t*, size_t));
+    MOCK_CONST_METHOD4(getaddrinfo,
+                       int(const char*, const char*, const struct addrinfo*,
+                           struct addrinfo**));
+    MOCK_CONST_METHOD1(freeaddrinfo, void(struct addrinfo*));
     MOCK_CONST_METHOD1(getSize, std::int64_t(const char*));
 };