Changeset 44c9ef4 in mainline

Timestamp:

2013-07-18T17:14:32Z (11 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

0aa70f4

Parents:

34c1bba

Message:

IPv6 fragmentation support

Location:

uspace/srv/net/inetsrv

Files:

• inet_std.h (modified) (2 diffs)
• pdu.c (modified) (12 diffs)

uspace/srv/net/inetsrv/inet_std.h

@@ -39 +39 @@
 
 #include <sys/types.h>
+
+#define IP6_NEXT_FRAGMENT  44
 
 /** IPv4 Datagram header (fixed part) */
@@ -90 +92 @@
 };
 
-/** Bits in ip6_frag_header_t.offsmf */
+/** Bits in ip6_header_fragment_t.offsmf */
 enum flags_offsmt_bits {
         /** More fragments */

uspace/srv/net/inetsrv/pdu.c

@@ -114 +114 @@
         
         size_t hdr_size = sizeof(ip_header_t);
-        
-        size_t data_offs = ROUND_UP(hdr_size, 4);
-        
+        if (hdr_size >= mtu)
+                return EINVAL;
+        
+        assert(hdr_size % 4 == 0);
         assert(offs % FRAG_OFFS_UNIT == 0);
         assert(offs / FRAG_OFFS_UNIT < fragoff_limit);
@@ -122 +123 @@
         /* Value for the fragment offset field */
         uint16_t foff = offs / FRAG_OFFS_UNIT;
-        
-        if (hdr_size >= mtu)
-                return EINVAL;
         
         /* Amount of space in the PDU available for payload */
@@ -170 +168 @@
         
         /* Copy payload */
-        memcpy((uint8_t *) data + data_offs, packet->data + offs, xfer_size);
+        memcpy((uint8_t *) data + hdr_size, packet->data + offs, xfer_size);
         
         *rdata = data;
@@ -194 +192 @@
  * @param rdata  Place to store pointer to allocated data buffer
  * @param rsize  Place to store size of allocated data buffer
- * @param roffs Place to store offset of remaning data
+ * @param roffs  Place to store offset of remaning data
  *
  */
@@ -200 +198 @@
     size_t offs, size_t mtu, void **rdata, size_t *rsize, size_t *roffs)
 {
+        /* IPv6 mandates a minimal MTU of 1280 bytes */
+        if (mtu < 1280)
+                return ELIMIT;
+        
         /* Upper bound for fragment offset field */
-        size_t fragoff_limit = 1 << (FF_FRAGOFF_h - FF_FRAGOFF_l);
+        size_t fragoff_limit = 1 << (OF_FRAGOFF_h - OF_FRAGOFF_l);
         
         /* Verify that total size of datagram is within reasonable bounds */
@@ -207 +209 @@
                 return ELIMIT;
         
-        size_t hdr_size = sizeof(ip6_header_t);
-        
-        size_t data_offs = ROUND_UP(hdr_size, 4);
-        
+        /* Determine whether we need the Fragment extension header */
+        bool fragment;
+        if (offs == 0)
+                fragment = (packet->size + sizeof(ip6_header_t) > mtu);
+        else
+                fragment = true;
+        
+        size_t hdr_size;
+        if (fragment)
+                hdr_size = sizeof(ip6_header_t) + sizeof(ip6_header_fragment_t);
+        else
+                hdr_size = sizeof(ip6_header_t);
+        
+        if (hdr_size >= mtu)
+                return EINVAL;
+        
+        assert(sizeof(ip6_header_t) % 8 == 0);
+        assert(hdr_size % 8 == 0);
         assert(offs % FRAG_OFFS_UNIT == 0);
         assert(offs / FRAG_OFFS_UNIT < fragoff_limit);
         
-#if 0
-        // FIXME TODO fragmentation
-        
         /* Value for the fragment offset field */
         uint16_t foff = offs / FRAG_OFFS_UNIT;
-#endif
-        
-        if (hdr_size >= mtu)
-                return EINVAL;
         
         /* Amount of space in the PDU available for payload */
@@ -237 +246 @@
         size_t rem_offs = offs + xfer_size;
         
-#if 0
-        // FIXME TODO fragmentation
-        
         /* Flags */
-        uint16_t flags_foff =
-            (packet->df ? BIT_V(uint16_t, FF_FLAG_DF) : 0) +
-            (rem_offs < packet->size ? BIT_V(uint16_t, FF_FLAG_MF) : 0) +
-            (foff << FF_FRAGOFF_l);
-#endif
+        uint16_t offsmf =
+            (rem_offs < packet->size ? BIT_V(uint16_t, OF_FLAG_M) : 0) +
+            (foff << OF_FRAGOFF_l);
         
         void *data = calloc(size, 1);
@@ -256 +260 @@
         hdr6->ver_tc = (6 << (VI_VERSION_l));
         memset(hdr6->tc_fl, 0, 3);
-        hdr6->payload_len = host2uint16_t_be(packet->size);
-        hdr6->next = packet->proto;
         hdr6->hop_limit = packet->ttl;
         
@@ -263 +265 @@
         host2addr128_t_be(dest, hdr6->dest_addr);
         
+        /* Optionally encode Fragment extension header fields */
+        if (fragment) {
+                assert(offsmf != 0);
+                
+                hdr6->payload_len = host2uint16_t_be(packet->size +
+                    sizeof(ip6_header_fragment_t));
+                hdr6->next = IP6_NEXT_FRAGMENT;
+                
+                ip6_header_fragment_t *hdr6f = (ip6_header_fragment_t *)
+                    (hdr6 + 1);
+                
+                hdr6f->next = packet->proto;
+                hdr6f->reserved = 0;
+                hdr6f->offsmf = host2uint16_t_be(offsmf);
+                hdr6f->id = host2uint32_t_be(packet->ident);
+        } else {
+                assert(offsmf == 0);
+                
+                hdr6->payload_len = host2uint16_t_be(packet->size);
+                hdr6->next = packet->proto;
+        }
+        
         /* Copy payload */
-        memcpy((uint8_t *) data + data_offs, packet->data + offs, xfer_size);
+        memcpy((uint8_t *) data + hdr_size, packet->data + offs, xfer_size);
         
         *rdata = data;
@@ -378 +402 @@
         size_t payload_len = uint16_t_be2host(hdr6->payload_len);
         if (payload_len + sizeof(ip6_header_t) > size) {
-                log_msg(LOG_DEFAULT, LVL_DEBUG, "Total Length = %zu > PDU size = %zu",
+                log_msg(LOG_DEFAULT, LVL_DEBUG, "Payload Length = %zu > PDU size = %zu",
                     payload_len + sizeof(ip6_header_t), size);
                 return EINVAL;
         }
         
-#if 0
-        // FIXME TODO fragmentation
-        
-        uint16_t ident = uint16_t_be2host(hdr->id);
-        uint16_t flags_foff = uint16_t_be2host(hdr->flags_foff);
-        uint16_t foff = BIT_RANGE_EXTRACT(uint16_t, FF_FRAGOFF_h, FF_FRAGOFF_l,
-            flags_foff);
-#endif
-        
-        /* XXX Checksum */
+        uint32_t ident;
+        uint16_t offsmf;
+        uint16_t foff;
+        uint16_t next;
+        size_t data_offs = sizeof(ip6_header_t);
+        
+        /* Fragment extension header */
+        if (hdr6->next == IP6_NEXT_FRAGMENT) {
+                ip6_header_fragment_t *hdr6f = (ip6_header_fragment_t *)
+                    (hdr6 + 1);
+                
+                ident = uint32_t_be2host(hdr6f->id);
+                offsmf = uint16_t_be2host(hdr6f->offsmf);
+                foff = BIT_RANGE_EXTRACT(uint16_t, OF_FRAGOFF_h, OF_FRAGOFF_l,
+                    offsmf);
+                next = hdr6f->next;
+                data_offs += sizeof(ip6_header_fragment_t);
+                payload_len -= sizeof(ip6_header_fragment_t);
+        } else {
+                ident = 0;
+                offsmf = 0;
+                foff = 0;
+                next = hdr6->next;
+        }
         
         addr128_t src;
@@ -404 +442 @@
         
         packet->tos = 0;
-        packet->proto = hdr6->next;
+        packet->proto = next;
         packet->ttl = hdr6->hop_limit;
-        
-#if 0
-        // FIXME TODO fragmentation
-        
         packet->ident = ident;
-        packet->df = (flags_foff & BIT_V(uint16_t, FF_FLAG_DF)) != 0;
-        packet->mf = (flags_foff & BIT_V(uint16_t, FF_FLAG_MF)) != 0;
+        
+        packet->df = 1;
+        packet->mf = (offsmf & BIT_V(uint16_t, OF_FLAG_M)) != 0;
         packet->offs = foff * FRAG_OFFS_UNIT;
-        
-        /* XXX IP options */
-        size_t data_offs = sizeof(uint32_t) *
-            BIT_RANGE_EXTRACT(uint8_t, VI_IHL_h, VI_IHL_l, hdr->ver_ihl);
-#endif
-        
-        packet->ident = 0;
-        packet->df = 0;
-        packet->mf = 0;
-        packet->offs = 0;
         
         packet->size = payload_len;
@@ -432 +457 @@
         }
         
-        memcpy(packet->data, (uint8_t *) data + sizeof(ip6_header_t), packet->size);
+        memcpy(packet->data, (uint8_t *) data + data_offs, packet->size);
         
         return EOK;