Segmentize outgoing packets.

[utcp] / utcp.c

diff --git a/utcp.c b/utcp.c
index e6f70f7b5c18f4ad83dbe427418186837ab24e8d..91aee3ce090f257e2d562b520e3ae59239012f33 100644 (file)
--- a/utcp.c
+++ b/utcp.c
@@ -210,7 +210,7 @@ static void free_connection(struct utcp_connection *c) {
 
 static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t src, uint16_t dst) {
        // Check whether this combination of src and dst is free
-       
+
        if(src) {
                if(find_connection(utcp, src, dst)) {
                        errno = EADDRINUSE;
@@ -256,6 +256,10 @@ static struct utcp_connection *allocate_connection(struct utcp *utcp, uint16_t s
        c->snd.nxt = c->snd.iss + 1;
        c->rcv.wnd = utcp->mtu;
        c->utcp = utcp;
+       c->sndbufsize = 65536;
+       c->sndbuf = malloc(c->sndbufsize);
+       if(!c->sndbuf)
+               c->sndbufsize = 0;
 
        // Add it to the sorted list of connections
 
@@ -302,7 +306,7 @@ void utcp_accept(struct utcp_connection *c, utcp_recv_t recv, void *priv) {
        set_state(c, ESTABLISHED);
 }
 
-int utcp_send(struct utcp_connection *c, void *data, size_t len) {
+ssize_t utcp_send(struct utcp_connection *c, void *data, size_t len) {
        if(c->reapable) {
                fprintf(stderr, "Error: send() called on closed connection %p\n", c);
                errno = EBADF;
@@ -330,6 +334,8 @@ int utcp_send(struct utcp_connection *c, void *data, size_t len) {
                return -1;
        }
 
+       // Add data to send buffer
+
        if(!len)
                return 0;
 
@@ -338,30 +344,43 @@ int utcp_send(struct utcp_connection *c, void *data, size_t len) {
                return -1;
        }
 
-       
+       uint32_t bufused = c->snd.nxt - c->snd.una;
+
+       if(len > c->sndbufsize - bufused)
+               len = c->sndbufsize - bufused;
+
+       memcpy(c->sndbuf + (c->snd.nxt - c->snd.una), data, len);
+
+       // Send segments
+
        struct {
                struct hdr hdr;
-               char data[len];
+               char data[c->utcp->mtu];
        } pkt;
 
        pkt.hdr.src = c->src;
        pkt.hdr.dst = c->dst;
-       pkt.hdr.seq = c->snd.nxt;
        pkt.hdr.ack = c->rcv.nxt;
        pkt.hdr.wnd = c->snd.wnd;
        pkt.hdr.ctl = ACK;
 
-       memcpy(pkt.data, data, len);
+       uint32_t left = len;
 
-       c->snd.nxt += len;
+       while(left) {
+               uint32_t seglen = left > c->utcp->mtu ? c->utcp->mtu : left;
+               pkt.hdr.seq = c->snd.nxt;
 
-       c->utcp->send(c->utcp, &pkt, sizeof pkt.hdr + len);
-       //
-       // Can we add it to the send window?
-       
-       // Do we need to kick some timers?
-       
-       return 0;
+               memcpy(pkt.data, data, seglen);
+
+               c->snd.nxt += seglen;
+               data += seglen;
+               left -= seglen;
+
+               c->utcp->send(c->utcp, &pkt, sizeof pkt.hdr + seglen);
+       }
+
+       fprintf(stderr, "len=%u\n", len);
+       return len;
 }
 
 static void swap_ports(struct hdr *hdr) {
@@ -370,6 +389,10 @@ static void swap_ports(struct hdr *hdr) {
        hdr->dst = tmp;
 }
 
+static int16_t seqdiff(uint16_t a, uint16_t b) {
+       return a -b;
+}
+
 int utcp_recv(struct utcp *utcp, void *data, size_t len) {
        if(!utcp) {
                errno = EFAULT;
@@ -441,10 +464,10 @@ int utcp_recv(struct utcp *utcp, void *data, size_t len) {
        }
 
        // It is for an existing connection.
-       
+
        if(c->state == SYN_SENT) {
                if(hdr.ctl & ACK) {
-                       if(hdr.ack <= c->snd.iss || hdr.ack > c->snd.nxt) {
+                       if(seqdiff(hdr.ack, c->snd.iss) <= 0 || seqdiff(hdr.ack, c->snd.nxt) > 0) {
                                fprintf(stderr, "Invalid ACK, %u %u %u\n", hdr.ack, c->snd.iss, c->snd.nxt);
                                goto reset;
                        }
@@ -465,7 +488,7 @@ int utcp_recv(struct utcp *utcp, void *data, size_t len) {
 
                        if(hdr.ctl & ACK)
                                c->snd.una = hdr.ack;
-                       if(c->snd.una > c->snd.iss) {
+                       if(seqdiff(c->snd.una, c->snd.iss) > 0) {
                                set_state(c, ESTABLISHED);
                                // TODO: signal app?
                                swap_ports(&hdr);
@@ -510,7 +533,7 @@ int utcp_recv(struct utcp *utcp, void *data, size_t len) {
        c->snd.wnd = hdr.wnd;
 
        // TODO: check whether segment really starts at rcv.nxt, otherwise trim it.
-       
+
        if(hdr.ctl & RST) {
                switch(c->state) {
                case SYN_RECEIVED:
@@ -563,7 +586,7 @@ int utcp_recv(struct utcp *utcp, void *data, size_t len) {
 
        switch(c->state) {
        case SYN_RECEIVED:
-               if(hdr.ack >= c->snd.una && hdr.ack <= c->snd.nxt)
+               if(seqdiff(hdr.ack, c->snd.una) >= 0 && seqdiff(hdr.ack, c->snd.nxt) <= 0)
                        c->utcp->accept(c, hdr.dst);
                
                if(c->state != ESTABLISHED)
@@ -571,13 +594,13 @@ int utcp_recv(struct utcp *utcp, void *data, size_t len) {
                break;
        case ESTABLISHED:
        case CLOSE_WAIT:
-               if(hdr.ack < c->snd.una)
+               if(seqdiff(hdr.ack, c->snd.una) < 0)
                        return 0;
-               if(hdr.ack > c->snd.nxt)
+               if(seqdiff(hdr.ack, c->snd.nxt) > 0)
                        goto ack_and_drop;
-               if(hdr.ack > c->snd.una && hdr.ack <= c->snd.nxt) {
+               if(seqdiff(hdr.ack, c->snd.una) > 0 && seqdiff(hdr.ack, c->snd.nxt) <= 0) {
                        c->snd.una = hdr.ack;
-                       if(c->snd.wl1 < hdr.seq || (c->snd.wl1 == hdr.seq && c->snd.wl2 <= hdr.ack)) {
+                       if(seqdiff(c->snd.wl1, hdr.seq) < 0 || (c->snd.wl1 == hdr.seq && seqdiff(c->snd.wl2, hdr.ack) <= 0)) {
                                c->snd.wnd = hdr.wnd;
                                c->snd.wl1 = hdr.seq;
                                c->snd.wl2 = hdr.ack;
@@ -655,7 +678,7 @@ int utcp_recv(struct utcp *utcp, void *data, size_t len) {
        }
 
        // Process the data
-       
+
        if(len && c->recv) {
                c->recv(c, data, len);
                c->rcv.nxt += len;