1 files changed, 109 insertions, 0 deletions
diff --git a/econpacket.c b/econpacket.c
new file mode 100644
index 0000000..58842cb
--- /dev/null
+++ b/econpacket.c
@@ -0,0 +1,109 @@
+#include <stdio.h>
+#include <string.h>
+
+#include <unistd.h>
+#include <sys/uio.h>
+
+#include "econpacket.h"
+#include "econproto.h"
+
+static void
+init_iov(struct econ_packet *pkt)
+{
+	pkt->iov[0].iov_base = &pkt->hdr;
+	pkt->iov[0].iov_len = sizeof pkt->hdr;
+	pkt->iov[1].iov_base = &pkt->cmd;
+	pkt->iov[1].iov_len = sizeof pkt->cmd;
+	pkt->iov[2].iov_base = &pkt->rec;
+	pkt->iov[2].iov_len = sizeof pkt->rec;
+}
+
+static void
+init_header(struct econ_header *ehdr, int cmd)
+{
+	memset(ehdr, 0, sizeof *ehdr);
+
+	strncpy(ehdr->magicnum, ECON_MAGIC_NUMBER,  ECON_MAGICNUM_SIZE);
+	strncpy(ehdr->version,  ECON_PROTO_VERSION, ECON_PROTOVER_MAXLEN);
+
+	ehdr->datasize = 0;
+	ehdr->commandID = cmd;
+}
+
+void
+epkt_init(struct econ_packet *pkt, int cmd)
+{
+	init_iov(pkt);
+
+	memset(&pkt->rec, 0, sizeof pkt->rec);
+	memset(&pkt->cmd, 0, sizeof pkt->cmd);
+	init_header(&pkt->hdr, cmd);
+}
+
+int
+epkt_send(int fd, struct econ_packet *pkt)
+{
+	int i = 1;
+
+	if (pkt->hdr.datasize > 0) {
+		i++;
+		if (pkt->cmd.recordCount == 1)
+			i++;
+	}
+
+	return writev(fd, pkt->iov, i);
+}
+
+int
+epkt_read(int fd, struct econ_packet *pkt)
+{
+	union { ssize_t s; size_t u; } len;
+
+	init_iov(pkt);
+
+	len.s = readv(fd, pkt->iov, 3);
+	if (len.s < 0)
+		return -1;
+
+	if (len.u < sizeof(struct econ_header)) {
+		fprintf(stderr, "epkt_read: error: incomplete header\n");
+		return -1;
+	}
+
+	if (len.u < sizeof(struct econ_header) + pkt->hdr.datasize) {
+		fprintf(stderr, "packet has invalid datasize\n");
+		return -1;
+	}
+
+	if (pkt->hdr.datasize > 0) {
+		if (pkt->hdr.datasize < sizeof(struct econ_command)) {
+			fprintf(stderr,
+				"epkt_read: error: command to short\n");
+			return -1;
+		}
+
+		/* Keepalive is an irregular if datasize > 0:
+		 *  the regular field recordCount is 1,
+		 *  without actually having one. */
+		if (pkt->hdr.commandID == E_CMD_KEEPALIVE)
+			return 0;
+
+		if (pkt->cmd.recordCount > 0) {
+			if (pkt->cmd.recordCount > 1) {
+				fprintf(stderr, "epkt_read:"
+					" did not expect a packet with more"
+					" that one record: %d, datasize: %d.\n",
+					pkt->cmd.recordCount, pkt->hdr.datasize);
+				return -1;
+			}
+			if (pkt->hdr.datasize != (sizeof (struct econ_command) +
+						  sizeof (struct econ_record))) {
+				fprintf(stderr, "epkt_read: datasize incorrect, cmd: %d\n",
+					pkt->hdr.commandID);
+				return -1;
+			}
+		}
+	}
+
+	return 0;
+}