dgram: Add datagram send interface

Signed-off-by: Ian Moffett <ian@osmora.org>

3 files changed, 94 insertions, 24 deletions

diff --git a/src/dgram/dgram_link.c b/src/dgram/dgram_link.c
new file mode 100644
index 0000000..718201b
--- /dev/null
+++ b/src/dgram/dgram_link.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <linux/if_packet.h>
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <stdlib.h>
+#include <string.h>
+#include "if_ether.h"
+#include "dgram.h"
+
+tx_len_t
+dgram_send(struct onet_link *link, void *buf, uint16_t len)
+{
+    struct sockaddr_ll saddr;
+    struct ether_hdr *eth;
+    struct onet_dgram *dgram;
+    size_t dgram_len;
+    char *p, *data;
+
+    dgram_len = DGRAM_LEN(len);
+    p = malloc(dgram_len);
+    if (p == NULL) {
+        return -1;
+    }
+
+    eth = (struct ether_hdr *)p;
+    data = DGRAM_DATA(p);
+    dgram = DGRAM_HDR(p);
+
+    /* Copy data to send buffer */
+    memset(data, 0, len);
+    memcpy(data, buf, len);
+
+    /*
+     * Set up link layer sockaddr, load up the frame, datagram
+     * and send it off.
+     */
+    saddr.sll_ifindex = link->iface_idx;
+    saddr.sll_halen = HW_ADDR_LEN;
+    ether_load_route(link->hwaddr, 0xFFFFFFFFFFFF, eth);
+    dgram_load(len, 50, dgram);
+    sendto(
+        link->sockfd, p, dgram_len, 0,
+        (struct sockaddr *)&saddr, sizeof(struct sockaddr_ll)
+    );
+
+    free(p);
+    return len;
+}
diff --git a/src/include/dgram.h b/src/include/dgram.h
index 93b20e3..e67eee6 100644
--- a/src/include/dgram.h
+++ b/src/include/dgram.h
@@ -32,6 +32,9 @@
 
 #include <stdint.h>
 #include "if_ether.h"
+#include "link.h"
+
+typedef int16_t tx_len_t;
 
 /*
  * Represents an ONET datagram
@@ -84,4 +87,16 @@ struct onet_dgram {
  */
 int dgram_load(uint16_t length, uint8_t port, struct onet_dgram *res);
 
+/*
+ * Send a datagram through ONET
+ *
+ * @link: The ONET link to send data over
+ * @buf: The buffer containing data to send
+ * @len: Length of buffer to send
+ *
+ * Returns the number of bytes transmitted on success, otherwise
+ * a less than zero value on failure.
+ */
+tx_len_t dgram_send(struct onet_link *link, void *buf, uint16_t len);
+
 #endif  /* DGRAM_H */
diff --git a/src/main.c b/src/main.c
index 98f8909..77a6c5a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -59,39 +59,16 @@ help(char **argv)
 static int
 data_send(void)
 {
-    char data[DGRAM_LEN(128)], *p;
-    struct sockaddr_ll saddr;
-    struct ether_hdr *eth;
-    struct onet_dgram *dgram;
     struct onet_link link;
     int error;
 
-    eth = (struct ether_hdr *)data;
-    p = DGRAM_DATA(data);
-    dgram = DGRAM_HDR(data);
-
-    memset(data, 0, sizeof(data));
-    memcpy(p, TEST_STR, sizeof(TEST_STR));
-
     /* Open a link */
     error = onet_open(iface, &link);
     if (error < 0) {
         return error;
     }
 
-    /*
-     * Set up link layer sockaddr, load up the frame, datagram
-     * and send it off.
-     */
-    saddr.sll_ifindex = link.iface_idx;
-    saddr.sll_halen = ETH_ALEN;
-    ether_load_route(link.hwaddr, 0xFFFFFFFFFFFF, eth);
-    dgram_load(sizeof(TEST_STR), 50, dgram);
-    sendto(
-        link.sockfd, &data, sizeof(data), 0,
-        (struct sockaddr *)&saddr, sizeof(struct sockaddr_ll)
-    );
-
+    dgram_send(&link, TEST_STR, sizeof(TEST_STR));
     onet_close(&link);
     return 0;
 }