feature: packet manager support build packet

infra/packet_manager/packet_builder.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#include "stellar/packet.h"
+
+/*
+ * tcp_seq: the sequence number of the new TCP packet (in host byte order)
+ * tcp_ack: the acknowledgment number of the new TCP packet (in host byte order)
+ * tcp_options_len: the length of the options (must be a multiple of 4)
+ */
+struct packet *packet_build_tcp(const struct packet *origin_pkt, uint32_t tcp_seq, uint32_t tcp_ack, uint8_t tcp_flags,
+                                const char *tcp_options, uint16_t tcp_options_len,
+                                const char *tcp_payload, uint16_t tcp_payload_len);
+struct packet *packet_build_udp(const struct packet *origin_pkt, const char *udp_payload, uint16_t udp_payload_len);
+struct packet *packet_build_l3(const struct packet *origin_pkt, uint8_t ip_proto, const char *l3_payload, uint16_t l3_payload_len);
+
+#ifdef __cplusplus
+}
+#endif