net: Use g_new() & friends where that makes obvious sense

g_new(T, n) is neater than g_malloc(sizeof(T) * n).  It's also safer,
for two reasons.  One, it catches multiplication overflowing size_t.
Two, it returns T * rather than void *, which lets the compiler catch
more type errors.

This commit only touches allocations with size arguments of the form
sizeof(T).

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

net/l2tpv3.c

@@ -489,12 +489,12 @@ static struct mmsghdr *build_l2tpv3_vector(NetL2TPV3State *s, int count)
     struct iovec *iov;
     struct mmsghdr *msgvec, *result;
 
-    msgvec = g_malloc(sizeof(struct mmsghdr) * count);
+    msgvec = g_new(struct mmsghdr, count);
     result = msgvec;
     for (i = 0; i < count ; i++) {
         msgvec->msg_hdr.msg_name = NULL;
         msgvec->msg_hdr.msg_namelen = 0;
-        iov =  g_malloc(sizeof(struct iovec) * IOVSIZE);
+        iov =  g_new(struct iovec, IOVSIZE);
         msgvec->msg_hdr.msg_iov = iov;
         iov->iov_base = g_malloc(s->header_size);
         iov->iov_len = s->header_size;
@@ -729,7 +729,7 @@ int net_init_l2tpv3(const NetClientOptions *opts,
     }
 
     s->msgvec = build_l2tpv3_vector(s, MAX_L2TPV3_MSGCNT);
-    s->vec = g_malloc(sizeof(struct iovec) * MAX_L2TPV3_IOVCNT);
+    s->vec = g_new(struct iovec, MAX_L2TPV3_IOVCNT);
     s->header_buf = g_malloc(s->header_size);
 
     qemu_set_nonblock(fd);

net/queue.c

@@ -62,7 +62,7 @@ NetQueue *qemu_new_net_queue(void *opaque)
 {
     NetQueue *queue;
 
-    queue = g_malloc0(sizeof(NetQueue));
+    queue = g_new0(NetQueue, 1);
 
     queue->opaque = opaque;
     queue->nq_maxlen = 10000;

net/slirp.c

@@ -652,7 +652,7 @@ static int slirp_guestfwd(SlirpState *s, const char *config_str,
             return -1;
         }
     } else {
-        fwd = g_malloc(sizeof(struct GuestFwd));
+        fwd = g_new(struct GuestFwd, 1);
         fwd->hd = qemu_chr_new(buf, p, NULL);
         if (!fwd->hd) {
             error_report("could not open guest forwarding device '%s'", buf);