Initial import, still work in progress

1 files changed, 97 insertions, 0 deletions

diff --git a/pkt.h b/pkt.h
new file mode 100644
index 0000000..e5f8c82
--- /dev/null
+++ b/pkt.h
@@ -0,0 +1,97 @@
+/*
+ * Packet buffer structure and utilities.
+ *
+ * Based on pkt_buff.h from the netsniff-ng toolkit.
+ *
+ * Copyright (C) 2015 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2012 Christoph Jaeger
+ *
+ * This file is part of llmnrd.
+ *
+ * llmnrd is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ *
+ * llmnrd is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with llmnrd.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef PKT_H
+#define PKT_H
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "util.h"
+
+struct pkt {
+	uint8_t *head;
+	uint8_t *data;
+	uint8_t *tail;
+	size_t size;
+};
+
+static inline bool pkt_invariant(struct pkt *p)
+{
+	return p && (p->head <= p->data) && (p->data <= p->tail);
+}
+
+static inline struct pkt *pkt_alloc(size_t size)
+{
+	struct pkt *p = xmalloc(sizeof(*q) + size);
+	uint8_t *data = (uint8_t *)p + sizeof(*p);
+
+	p->head = data;
+	p->data = data;
+	p->tail = data + size;
+	p->size = size;
+
+	return p;
+}
+
+static inline void pkt_free(struct pkt *p)
+{
+	free(p);
+}
+
+static inline size_t pkt_len(struct pkt *p)
+{
+	assert(pkt_invariant(p));
+
+	return p->tail - p->data;
+}
+
+static inline uint8_t *pkt_put(struct pkt *p, size_t len)
+{
+	uint8_t *data = NULL;
+
+	assert(pkt_invariant(p));
+
+	if (len <= pkt_len(p)) {
+		data = p->tail;
+		p->tail += len;
+	} else
+		assert(false);	/* TODO */
+
+	return data;
+}
+
+static inline void pkt_put_u16(struct pkt *p, uint16_t val)
+{
+	uint16_t *data = (uint16_t *)pkt_put(p, sizeof(val));
+	*data = val;
+}
+
+static inline void pkt_put_u32(struct pkt *p, uint32_t val)
+{
+	uint32_t *data = (uint32_t *)pkt_put(p, sizeof(val));
+	*data = val;
+}
+
+#endif /* PKT_H */