diff --git a/include/net/net.h b/include/net/net.h
index 73e4c46..1439cf9 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -102,6 +102,14 @@ typedef struct NICState {
     bool peer_deleted;
 } NICState;
 
+typedef struct ReadState {
+    int state; /* 0 = getting length, 1 = getting data */
+    uint32_t index;
+    uint32_t packet_len;
+    uint8_t buf[NET_BUFSIZE];
+} ReadState;
+
+int net_fill_rstate(ReadState *rs, const uint8_t *buf, int size);
 char *qemu_mac_strdup_printf(const uint8_t *macaddr);
 NetClientState *qemu_find_netdev(const char *id);
 int qemu_find_net_clients_except(const char *id, NetClientState **ncs,
diff --git a/net/filter-mirror.c b/net/filter-mirror.c
index c0c4dc6..bcec509 100644
--- a/net/filter-mirror.c
+++ b/net/filter-mirror.c
@@ -40,10 +40,7 @@ typedef struct MirrorState {
     char *outdev;
     CharDriverState *chr_in;
     CharDriverState *chr_out;
-    int state; /* 0 = getting length, 1 = getting data */
-    unsigned int index;
-    unsigned int packet_len;
-    uint8_t buf[REDIRECTOR_MAX_LEN];
+    ReadState rs;
 } MirrorState;
 
 static int filter_mirror_send(CharDriverState *chr_out,
@@ -108,51 +105,14 @@ static void redirector_chr_read(void *opaque, const uint8_t *buf, int size)
 {
     NetFilterState *nf = opaque;
     MirrorState *s = FILTER_REDIRECTOR(nf);
-    unsigned int l;
-
-    while (size > 0) {
-        /* reassemble a packet from the network */
-        switch (s->state) { /* 0 = getting length, 1 = getting data */
-        case 0:
-            l = 4 - s->index;
-            if (l > size) {
-                l = size;
-            }
-            memcpy(s->buf + s->index, buf, l);
-            buf += l;
-            size -= l;
-            s->index += l;
-            if (s->index == 4) {
-                /* got length */
-                s->packet_len = ntohl(*(uint32_t *)s->buf);
-                s->index = 0;
-                s->state = 1;
-            }
-            break;
-        case 1:
-            l = s->packet_len - s->index;
-            if (l > size) {
-                l = size;
-            }
-            if (s->index + l <= sizeof(s->buf)) {
-                memcpy(s->buf + s->index, buf, l);
-            } else {
-                error_report("serious error: oversized packet received.");
-                s->index = s->state = 0;
-                qemu_chr_add_handlers(s->chr_in, NULL, NULL, NULL, NULL);
-                return;
-            }
-
-            s->index += l;
-            buf += l;
-            size -= l;
-            if (s->index >= s->packet_len) {
-                s->index = 0;
-                s->state = 0;
-                redirector_to_filter(nf, s->buf, s->packet_len);
-            }
-            break;
-        }
+    int ret;
+
+    ret = net_fill_rstate(&s->rs, buf, size);
+
+    if (ret == -1) {
+        qemu_chr_add_handlers(s->chr_in, NULL, NULL, NULL, NULL);
+    } else if (ret == 1) {
+        redirector_to_filter(nf, s->rs.buf, s->rs.packet_len);
     }
 }
 
@@ -274,7 +234,7 @@ static void filter_redirector_setup(NetFilterState *nf, Error **errp)
         }
     }
 
-    s->state = s->index = 0;
+    s->rs.state = s->rs.index = 0;
 
     if (s->indev) {
         s->chr_in = qemu_chr_find(s->indev);
diff --git a/net/net.c b/net/net.c
index 0ad6217..926457e 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1573,3 +1573,59 @@ QemuOptsList qemu_net_opts = {
         { /* end of list */ }
     },
 };
+
+/*
+ * Returns
+ * 0: readstate is not ready
+ * 1: readstate is ready
+ * otherwise error occurs
+ */
+int net_fill_rstate(ReadState *rs, const uint8_t *buf, int size)
+{
+    unsigned int l;
+    while (size > 0) {
+        /* reassemble a packet from the network */
+        switch (rs->state) { /* 0 = getting length, 1 = getting data */
+        case 0:
+            l = 4 - rs->index;
+            if (l > size) {
+                l = size;
+            }
+            memcpy(rs->buf + rs->index, buf, l);
+            buf += l;
+            size -= l;
+            rs->index += l;
+            if (rs->index == 4) {
+                /* got length */
+                rs->packet_len = ntohl(*(uint32_t *)rs->buf);
+                rs->index = 0;
+                rs->state = 1;
+            }
+            break;
+        case 1:
+            l = rs->packet_len - rs->index;
+            if (l > size) {
+                l = size;
+            }
+            if (rs->index + l <= sizeof(rs->buf)) {
+                memcpy(rs->buf + rs->index, buf, l);
+            } else {
+                fprintf(stderr, "serious error: oversized packet received,"
+                    "connection terminated.\n");
+                rs->index = rs->state = 0;
+                return -1;
+            }
+
+            rs->index += l;
+            buf += l;
+            size -= l;
+            if (rs->index >= rs->packet_len) {
+                rs->index = 0;
+                rs->state = 0;
+                return 1;
+            }
+            break;
+        }
+    }
+    return 0;
+}
diff --git a/net/socket.c b/net/socket.c
index 9fa2cd8..9ecdd3b 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -38,11 +38,8 @@ typedef struct NetSocketState {
     NetClientState nc;
     int listen_fd;
     int fd;
-    int state; /* 0 = getting length, 1 = getting data */
-    unsigned int index;
-    unsigned int packet_len;
+    ReadState rs;
     unsigned int send_index;      /* number of bytes sent (only SOCK_STREAM) */
-    uint8_t buf[NET_BUFSIZE];
     struct sockaddr_in dgram_dst; /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
     IOHandler *send_fn;           /* differs between SOCK_STREAM/SOCK_DGRAM */
     bool read_poll;               /* waiting to receive data? */
@@ -147,7 +144,7 @@ static void net_socket_send(void *opaque)
 {
     NetSocketState *s = opaque;
     int size;
-    unsigned l;
+    int ret;
     uint8_t buf1[NET_BUFSIZE];
     const uint8_t *buf;
 
@@ -166,60 +163,26 @@ static void net_socket_send(void *opaque)
         closesocket(s->fd);
 
         s->fd = -1;
-        s->state = 0;
-        s->index = 0;
-        s->packet_len = 0;
+        s->rs.state = 0;
+        s->rs.index = 0;
+        s->rs.packet_len = 0;
         s->nc.link_down = true;
-        memset(s->buf, 0, sizeof(s->buf));
+        memset(s->rs.buf, 0, sizeof(s->rs.buf));
         memset(s->nc.info_str, 0, sizeof(s->nc.info_str));
 
         return;
     }
     buf = buf1;
-    while (size > 0) {
-        /* reassemble a packet from the network */
-        switch(s->state) {
-        case 0:
-            l = 4 - s->index;
-            if (l > size)
-                l = size;
-            memcpy(s->buf + s->index, buf, l);
-            buf += l;
-            size -= l;
-            s->index += l;
-            if (s->index == 4) {
-                /* got length */
-                s->packet_len = ntohl(*(uint32_t *)s->buf);
-                s->index = 0;
-                s->state = 1;
-            }
-            break;
-        case 1:
-            l = s->packet_len - s->index;
-            if (l > size)
-                l = size;
-            if (s->index + l <= sizeof(s->buf)) {
-                memcpy(s->buf + s->index, buf, l);
-            } else {
-                fprintf(stderr, "serious error: oversized packet received,"
-                    "connection terminated.\n");
-                s->state = 0;
-                goto eoc;
-            }
 
-            s->index += l;
-            buf += l;
-            size -= l;
-            if (s->index >= s->packet_len) {
-                s->index = 0;
-                s->state = 0;
-                if (qemu_send_packet_async(&s->nc, s->buf, s->packet_len,
-                                           net_socket_send_completed) == 0) {
-                    net_socket_read_poll(s, false);
-                    break;
-                }
-            }
-            break;
+    ret = net_fill_rstate(&s->rs, buf, size);
+
+    if (ret == -1) {
+        goto eoc;
+    } else if (ret == 1) {
+        if (qemu_send_packet_async(&s->nc, s->rs.buf,
+                                   s->rs.packet_len,
+                                   net_socket_send_completed) == 0) {
+            net_socket_read_poll(s, false);
         }
     }
 }
@@ -229,7 +192,7 @@ static void net_socket_send_dgram(void *opaque)
     NetSocketState *s = opaque;
     int size;
 
-    size = qemu_recv(s->fd, s->buf, sizeof(s->buf), 0);
+    size = qemu_recv(s->fd, s->rs.buf, sizeof(s->rs.buf), 0);
     if (size < 0)
         return;
     if (size == 0) {
@@ -238,7 +201,7 @@ static void net_socket_send_dgram(void *opaque)
         net_socket_write_poll(s, false);
         return;
     }
-    if (qemu_send_packet_async(&s->nc, s->buf, size,
+    if (qemu_send_packet_async(&s->nc, s->rs.buf, size,
                                net_socket_send_completed) == 0) {
         net_socket_read_poll(s, false);
     }
