Index: uspace/srv/net/tcp/pdu.c
===================================================================
--- uspace/srv/net/tcp/pdu.c	(revision 02a09ed9ab72cd7eb2ca3f11873db078ab906acc)
+++ uspace/srv/net/tcp/pdu.c	(revision 1d24ad312b4ddcdf3dc7c30ee0effc5293fd669c)
@@ -145,5 +145,6 @@
 }
 
-static uint16_t tcp_phdr_setup(tcp_pdu_t *pdu, tcp_phdr_t *phdr)
+static uint16_t tcp_phdr_setup(tcp_pdu_t *pdu, tcp_phdr_t *phdr,
+    tcp_phdr6_t *phdr6)
 {
 	addr32_t src_v4;
@@ -167,6 +168,11 @@
 		break;
 	case AF_INET6:
-		// FIXME TODO
-		assert(false);
+		host2addr128_t_be(src_v6, phdr6->src);
+		host2addr128_t_be(dest_v6, phdr6->dest);
+		phdr6->tcp_length =
+		    host2uint32_t_be(pdu->header_size + pdu->text_size);
+		memset(phdr6->zero, 0, 3);
+		phdr6->next = IP_PROTO_TCP;
+		break;
 	default:
 		assert(false);
@@ -259,6 +265,7 @@
 	uint16_t cs_headers;
 	tcp_phdr_t phdr;
-	
-	uint16_t af = tcp_phdr_setup(pdu, &phdr);
+	tcp_phdr6_t phdr6;
+	
+	uint16_t af = tcp_phdr_setup(pdu, &phdr, &phdr6);
 	switch (af) {
 	case AF_INET:
@@ -267,6 +274,7 @@
 		break;
 	case AF_INET6:
-		// FIXME TODO
-		assert(false);
+		cs_phdr = tcp_checksum_calc(TCP_CHECKSUM_INIT, (void *) &phdr6,
+		    sizeof(tcp_phdr6_t));
+		break;
 	default:
 		assert(false);
Index: uspace/srv/net/tcp/std.h
===================================================================
--- uspace/srv/net/tcp/std.h	(revision 02a09ed9ab72cd7eb2ca3f11873db078ab906acc)
+++ uspace/srv/net/tcp/std.h	(revision 1d24ad312b4ddcdf3dc7c30ee0effc5293fd669c)
@@ -75,5 +75,5 @@
 };
 
-/** TCP pseudo header */
+/** TCP IPv4 pseudo header */
 typedef struct {
 	/** Source address */
@@ -88,4 +88,18 @@
 	uint16_t tcp_length;
 } tcp_phdr_t;
+
+/** TCP IPv6 pseudo header */
+typedef struct {
+	/** Source address */
+	addr128_t src;
+	/** Destination address */
+	addr128_t dest;
+	/** TCP length */
+	uint32_t tcp_length;
+	/** Zeroes */
+	uint8_t zero[3];
+	/** Next header */
+	uint8_t next;
+} tcp_phdr6_t;
 
 /** Option kind */