[PATCH v14 1/2] net: Add TCP protocol
Ying-Chun Liu
grandpaul at gmail.com
Thu Apr 21 18:54:22 CEST 2022
From: "Ying-Chun Liu (PaulLiu)" <paul.liu at linaro.org>
Currently file transfers are done using tftp or NFS both
over udp. This requires a request to be sent from client
(u-boot) to the boot server.
The current standard is TCP with selective acknowledgment.
Signed-off-by: Duncan Hare <DH at Synoia.com>
Signed-off-by: Duncan Hare <DuncanCHare at yahoo.com>
Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu at linaro.org>
Cc: Christian Gmeiner <christian.gmeiner at gmail.com>
Cc: Joe Hershberger <joe.hershberger at ni.com>
Cc: Ramon Fried <rfried.dev at gmail.com>
---
v13: Fix some issues which is reviewed by Christian
v14: Add options to enable/disable SACK.
---
include/net.h | 8 +-
include/net/tcp.h | 222 +++++++++++++++
net/Kconfig | 12 +
net/Makefile | 1 +
net/net.c | 30 ++
net/tcp.c | 709 ++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 981 insertions(+), 1 deletion(-)
create mode 100644 include/net/tcp.h
create mode 100644 net/tcp.c
diff --git a/include/net.h b/include/net.h
index 675bf4171b..220eba2e21 100644
--- a/include/net.h
+++ b/include/net.h
@@ -365,6 +365,7 @@ struct vlan_ethernet_hdr {
#define PROT_NCSI 0x88f8 /* NC-SI control packets */
#define IPPROTO_ICMP 1 /* Internet Control Message Protocol */
+#define IPPROTO_TCP 6 /* Transmission Control Protocol */
#define IPPROTO_UDP 17 /* User Datagram Protocol */
/*
@@ -687,7 +688,7 @@ static inline void net_send_packet(uchar *pkt, int len)
}
/*
- * Transmit "net_tx_packet" as UDP packet, performing ARP request if needed
+ * Transmit "net_tx_packet" as UDP or TCP packet, send ARP request if needed
* (ether will be populated)
*
* @param ether Raw packet buffer
@@ -695,10 +696,15 @@ static inline void net_send_packet(uchar *pkt, int len)
* @param dport Destination UDP port
* @param sport Source UDP port
* @param payload_len Length of data after the UDP header
+ * @param action TCP action to be performed
+ * @param tcp_seq_num TCP sequence number of this transmission
+ * @param tcp_ack_num TCP stream acknolegement number
*/
int net_send_ip_packet(uchar *ether, struct in_addr dest, int dport, int sport,
int payload_len, int proto, u8 action, u32 tcp_seq_num,
u32 tcp_ack_num);
+int net_send_tcp_packet(int payload_len, int dport, int sport, u8 action,
+ u32 tcp_seq_num, u32 tcp_ack_num);
int net_send_udp_packet(uchar *ether, struct in_addr dest, int dport,
int sport, int payload_len);
diff --git a/include/net/tcp.h b/include/net/tcp.h
new file mode 100644
index 0000000000..417a6d0f4e
--- /dev/null
+++ b/include/net/tcp.h
@@ -0,0 +1,222 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * TCP Support with SACK for file transfer.
+ *
+ * Copyright 2017 Duncan Hare, All rights reserved.
+ */
+
+#define TCP_ACTIVITY 127 /* Number of packets received */
+ /* before console progress mark */
+
+struct ip_tcp_hdr {
+ u8 ip_hl_v; /* header length and version */
+ u8 ip_tos; /* type of service */
+ u16 ip_len; /* total length */
+ u16 ip_id; /* identification */
+ u16 ip_off; /* fragment offset field */
+ u8 ip_ttl; /* time to live */
+ u8 ip_p; /* protocol */
+ u16 ip_sum; /* checksum */
+ struct in_addr ip_src; /* Source IP address */
+ struct in_addr ip_dst; /* Destination IP address */
+ u16 tcp_src; /* TCP source port */
+ u16 tcp_dst; /* TCP destination port */
+ u32 tcp_seq; /* TCP sequence number */
+ u32 tcp_ack; /* TCP Acknowledgment number */
+ u8 tcp_hlen; /* 4 bits TCP header Length/4 */
+ /* 4 bits Reserved */
+ /* 2 more bits reserved */
+ u8 tcp_flags; /* see defines */
+ u16 tcp_win; /* TCP windows size */
+ u16 tcp_xsum; /* Checksum */
+ u16 tcp_ugr; /* Pointer to urgent data */
+} __packed;
+
+#define IP_TCP_HDR_SIZE (sizeof(struct ip_tcp_hdr))
+#define TCP_HDR_SIZE (IP_TCP_HDR_SIZE - IP_HDR_SIZE)
+
+#define TCP_DATA 0x00 /* Data Packet - internal use only */
+#define TCP_FIN 0x01 /* Finish flag */
+#define TCP_SYN 0x02 /* Synch (start) flag */
+#define TCP_RST 0x04 /* reset flag */
+#define TCP_PUSH 0x08 /* Push - Notify app */
+#define TCP_ACK 0x10 /* Acknowledgment of data received */
+#define TCP_URG 0x20 /* Urgent */
+#define TCP_ECE 0x40 /* Congestion control */
+#define TCP_CWR 0x80 /* Congestion Control */
+
+/*
+ * TCP header options, Seq, MSS, and SACK
+ */
+
+#define TCP_SACK 32 /* Number of packets analyzed */
+ /* on leading edge of stream */
+
+#define TCP_O_END 0x00 /* End of option list */
+#define TCP_1_NOP 0x01 /* Single padding NOP */
+#define TCP_O_NOP 0x01010101 /* NOPs pad to 32 bit boundary */
+#define TCP_O_MSS 0x02 /* MSS Size option */
+#define TCP_O_SCL 0x03 /* Window Scale option */
+#define TCP_P_SACK 0x04 /* SACK permitted */
+#define TCP_V_SACK 0x05 /* SACK values */
+#define TCP_O_TS 0x08 /* Timestamp option */
+#define TCP_OPT_LEN_2 0x02
+#define TCP_OPT_LEN_3 0x03
+#define TCP_OPT_LEN_4 0x04
+#define TCP_OPT_LEN_6 0x06
+#define TCP_OPT_LEN_8 0x08
+#define TCP_OPT_LEN_A 0x0a /* Timestamp Length */
+
+/*
+ * Please review the warning in net.c about these two parameters.
+ * They are part of a promise of RX buffer size to the sending TCP
+ */
+
+#define TCP_MSS 1460 /* Max segment size */
+#define TCP_SCALE 0x01 /* Scale */
+
+struct tcp_mss { /* TCP Max Segment size */
+ u8 kind; /* Field ID */
+ u8 len; /* Field length */
+ u16 mss; /* Segment size value */
+} __packed;
+
+struct tcp_scale { /* TCP Windows Scale */
+ u8 kind; /* Field ID */
+ u8 len; /* Filed length */
+ u8 scale; /* windows shift value used for */
+ /* networks with many hops */
+ /* Typically 4 or more hops */
+} __packed;
+
+struct tcp_sack_p { /* SACK permitted */
+ u8 kind; /* Field Id */
+ u8 len; /* Field length */
+} __packed;
+
+struct sack_edges {
+ u32 l; /* Left edge of stream */
+ u32 r; /* right edge of stream */
+} __packed;
+
+#define TCP_SACK_SIZE (sizeof(struct sack_edges))
+
+/*
+ * A TCP stream has holes when packets are missing or disordered.
+ * A hill is the inverse of a hole, and is data received.
+ * TCP received hills (a sequence of data), and inferrs Holes
+ * from the "hills" or packets received.
+ */
+
+#define TCP_SACK_HILLS 4
+
+struct tcp_sack_v {
+ u8 kind; /* Field ID */
+ u8 len; /* Field Length */
+ struct sack_edges hill[TCP_SACK_HILLS]; /* L & R window edges */
+} __packed;
+
+struct tcp_t_opt { /* TCP time stamps option */
+ u8 kind; /* Field id */
+ u8 len; /* Field length */
+ u32 t_snd; /* Sender timestamp */
+ u32 t_rcv; /* Receiver timestamp */
+} __packed;
+
+#define TCP_TSOPT_SIZE (sizeof(struct tcp_t_opt))
+
+/*
+ * ip tcp structure with options
+ */
+
+struct ip_tcp_hdr_o {
+ struct ip_tcp_hdr hdr;
+ struct tcp_mss mss;
+ struct tcp_scale scale;
+ struct tcp_sack_p sack_p;
+ struct tcp_t_opt t_opt;
+ u8 end;
+} __packed;
+
+#define IP_TCP_O_SIZE (sizeof(struct ip_tcp_hdr_o))
+
+struct ip_tcp_hdr_s {
+ struct ip_tcp_hdr hdr;
+ struct tcp_t_opt t_opt;
+ struct tcp_sack_v sack_v;
+ u8 end;
+} __packed;
+
+#define IP_TCP_SACK_SIZE (sizeof(struct ip_tcp_hdr_s))
+
+/*
+ * TCP pseudo header definitions
+ */
+#define PSEUDO_PAD_SIZE 8
+
+struct pseudo_hdr {
+ u8 padding[PSEUDO_PAD_SIZE]; /* pseudo hdr size = ip_tcp hdr size */
+ struct in_addr p_src;
+ struct in_addr p_dst;
+ u8 rsvd;
+ u8 p;
+ u16 len;
+} __packed;
+
+#define PSEUDO_HDR_SIZE (sizeof(struct pseudo_hdr)) - PSEUDO_PAD_SIZE
+
+/*
+ * union for building TCP/IP packet. Build Pseudo header in packed buffer
+ * first, calculate TCP checksum, then build IP header in packed buffer.
+ */
+
+union tcp_build_pkt {
+ struct pseudo_hdr ph;
+ struct ip_tcp_hdr_o ip;
+ struct ip_tcp_hdr_s sack;
+ uchar raw[1600];
+} __packed;
+
+/*
+ * TCP State machine states for connection
+ */
+
+enum TCP_STATE {
+ TCP_CLOSED, /* Need to send SYN to connect */
+ TCP_SYN_SENT, /* Trying to connect, waiting for SYN ACK */
+ TCP_ESTABLISHED, /* both server & client have a connection */
+ TCP_CLOSE_WAIT, /* Rec FIN, passed to app for FIN, ACK rsp*/
+ TCP_CLOSING, /* Rec FIN, sent FIN, ACK waiting for ACK */
+ TCP_FIN_WAIT_1, /* Sent FIN waiting for response */
+ TCP_FIN_WAIT_2 /* Rec ACK from FIN sent, waiting for FIN */
+};
+
+enum TCP_STATE tcp_get_tcp_state(void);
+void tcp_set_tcp_state(enum TCP_STATE new_state);
+int tcp_set_tcp_header(uchar *pkt, int dport, int sport, int payload_len,
+ u8 action, u32 tcp_seq_num, u32 tcp_ack_num);
+
+/*
+ * An incoming packet handler.
+ * @param pkt pointer to the application packet
+ * @param dport destination UDP port
+ * @param sip source IP address
+ * @param sport source UDP port
+ * @param len packet length
+ */
+typedef void rxhand_tcp(uchar *pkt, unsigned int dport,
+ struct in_addr sip, unsigned int sport,
+ unsigned int len);
+void tcp_set_tcp_handler(rxhand_tcp *f);
+
+void rxhand_tcp_f(union tcp_build_pkt *b, unsigned int len);
+
+/*
+ * An incoming TCP packet handler for the TCP protocol.
+ * There is also a dynamic function pointer for TCP based commands to
+ * receive incoming traffic after the TCP protocol code has done its work.
+ */
+
+void rxhand_action(u8 tcp_action, int payload_len, u32 tcp_seq_num,
+ u32 tcp_ack_num, unsigned int pkt_len,
+ union tcp_build_pkt *b);
diff --git a/net/Kconfig b/net/Kconfig
index ef0aa161f7..73e4bcb88e 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -159,6 +159,18 @@ config BOOTP_SERVERIP
variable, not the BOOTP server. This affects the operation of both
bootp and tftp.
+config PROT_TCP
+ bool "TCP stack"
+ help
+ Enable a generic tcp framework that allows defining a custom
+ handler for tcp protocol.
+
+config PROT_TCP_SACK
+ bool "TCP SACK support"
+ help
+ TCP protocol with SACK. Selecting this will provide the fastest
+ file transfer possible.
+
endif # if NET
config SYS_RX_ETH_BUFFER
diff --git a/net/Makefile b/net/Makefile
index fb3eba840f..f68ad94767 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_CMD_TFTPBOOT) += tftp.o
obj-$(CONFIG_UDP_FUNCTION_FASTBOOT) += fastboot.o
obj-$(CONFIG_CMD_WOL) += wol.o
obj-$(CONFIG_PROT_UDP) += udp.o
+obj-$(CONFIG_PROT_TCP) += tcp.o
# Disable this warning as it is triggered by:
# sprintf(buf, index ? "foo%d" : "foo", index)
diff --git a/net/net.c b/net/net.c
index 072a82d8f9..28d9fbd227 100644
--- a/net/net.c
+++ b/net/net.c
@@ -116,6 +116,7 @@
#if defined(CONFIG_CMD_WOL)
#include "wol.h"
#endif
+#include <net/tcp.h>
/** BOOTP EXTENTIONS **/
@@ -386,6 +387,8 @@ int net_init(void)
/* Only need to setup buffer pointers once. */
first_call = 0;
+ if (IS_ENABLED(CONFIG_PROT_TCP))
+ tcp_set_tcp_state(TCP_CLOSED);
}
return net_init_loop();
@@ -816,6 +819,16 @@ int net_send_udp_packet(uchar *ether, struct in_addr dest, int dport, int sport,
IPPROTO_UDP, 0, 0, 0);
}
+#if defined(CONFIG_PROT_TCP)
+int net_send_tcp_packet(int payload_len, int dport, int sport, u8 action,
+ u32 tcp_seq_num, u32 tcp_ack_num)
+{
+ return net_send_ip_packet(net_server_ethaddr, net_server_ip, dport,
+ sport, payload_len, IPPROTO_TCP, action,
+ tcp_seq_num, tcp_ack_num);
+}
+#endif
+
int net_send_ip_packet(uchar *ether, struct in_addr dest, int dport, int sport,
int payload_len, int proto, u8 action, u32 tcp_seq_num,
u32 tcp_ack_num)
@@ -847,6 +860,14 @@ int net_send_ip_packet(uchar *ether, struct in_addr dest, int dport, int sport,
payload_len);
pkt_hdr_size = eth_hdr_size + IP_UDP_HDR_SIZE;
break;
+#if defined(CONFIG_PROT_TCP)
+ case IPPROTO_TCP:
+ pkt_hdr_size = eth_hdr_size +
+ tcp_set_tcp_header(pkt + eth_hdr_size, dport, sport,
+ payload_len, action, tcp_seq_num,
+ tcp_ack_num);
+ break;
+#endif
default:
return -EINVAL;
}
@@ -1253,6 +1274,15 @@ void net_process_received_packet(uchar *in_packet, int len)
if (ip->ip_p == IPPROTO_ICMP) {
receive_icmp(ip, len, src_ip, et);
return;
+#if defined(CONFIG_PROT_TCP)
+ } else if (ip->ip_p == IPPROTO_TCP) {
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP PH (to=%pI4, from=%pI4, len=%d)\n",
+ &dst_ip, &src_ip, len);
+
+ rxhand_tcp_f((union tcp_build_pkt *)ip, len);
+ return;
+#endif
} else if (ip->ip_p != IPPROTO_UDP) { /* Only UDP packets */
return;
}
diff --git a/net/tcp.c b/net/tcp.c
new file mode 100644
index 0000000000..ebd349c3e8
--- /dev/null
+++ b/net/tcp.c
@@ -0,0 +1,709 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2017 Duncan Hare, all rights reserved.
+ */
+
+/*
+ * General Desription:
+ *
+ * TCP support for the wget command, for fast file downloading.
+ *
+ * HTTP/TCP Receiver:
+ *
+ * Prerequisites: - own ethernet address
+ * - own IP address
+ * - Server IP address
+ * - Server with TCP
+ * - TCP application (eg wget)
+ * Next Step HTTPS?
+ */
+#include <common.h>
+#include <command.h>
+#include <console.h>
+#include <env_internal.h>
+#include <errno.h>
+#include <net.h>
+#include <net/tcp.h>
+
+/*
+ * TCP sliding window control used by us to request re-TX
+ */
+
+static struct tcp_sack_v tcp_lost;
+
+/* TCP option timestamp */
+static u32 loc_timestamp;
+static u32 rmt_timestamp;
+
+u32 tcp_seq_init;
+u32 tcp_ack_edge;
+u32 tcp_seq_max;
+
+int tcp_activity_count;
+
+/*
+ * Search for TCP_SACK and review the comments before the code section
+ * TCP_SACK is the number of packets at the front of the stream
+ */
+
+enum pkt_state {PKT, NOPKT};
+struct sack_r {
+ struct sack_edges se;
+ enum pkt_state st;
+};
+
+struct sack_r edge_a[TCP_SACK];
+unsigned int sack_idx;
+unsigned int prev_len;
+
+/* TCP connection state */
+static enum TCP_STATE tcp_state;
+
+/*
+ * An incoming TCP packet handler for the TCP protocol.
+ * There is also a dynamic function pointer for TCP based commands to
+ * receive incoming traffic after the TCP protocol code has done its work.
+ */
+
+/* Current TCP RX packet handler */
+static rxhand_tcp *tcp_packet_handler;
+
+enum TCP_STATE tcp_get_tcp_state(void)
+{
+ return tcp_state;
+}
+
+void tcp_set_tcp_state(enum TCP_STATE new_state)
+{
+ tcp_state = new_state;
+}
+
+static void dummy_handler(uchar *pkt, unsigned int dport,
+ struct in_addr sip, unsigned int sport,
+ unsigned int len)
+{
+}
+
+void tcp_set_tcp_handler(rxhand_tcp *f)
+{
+ debug_cond(DEBUG_INT_STATE, "--- net_loop TCP handler set (%p)\n", f);
+ if (!f)
+ tcp_packet_handler = dummy_handler;
+ else
+ tcp_packet_handler = f;
+}
+
+u16 tcp_set_pseudo_header(uchar *pkt, struct in_addr src, struct in_addr dest,
+ int tcp_len, int pkt_len)
+{
+ union tcp_build_pkt *b = (union tcp_build_pkt *)pkt;
+ int checksum_len;
+
+ /*
+ * Pseudo header
+ *
+ * Zero the byte after the last byte so that the header checksum
+ * will always work.
+ */
+
+ pkt[pkt_len] = 0x00;
+
+ net_copy_ip((void *)&b->ph.p_src, &src);
+ net_copy_ip((void *)&b->ph.p_dst, &dest);
+ b->ph.rsvd = 0x00;
+ b->ph.p = IPPROTO_TCP;
+ b->ph.len = htons(tcp_len);
+ checksum_len = tcp_len + PSEUDO_HDR_SIZE;
+
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP Pesudo Header (to=%pI4, from=%pI4, Len=%d)\n",
+ &b->ph.p_dst, &b->ph.p_src, checksum_len);
+
+ return compute_ip_checksum(pkt + PSEUDO_PAD_SIZE, checksum_len);
+}
+
+int net_set_ack_options(union tcp_build_pkt *b)
+{
+ b->sack.hdr.tcp_hlen = (TCP_HDR_SIZE >> 2) << 4;
+
+ b->sack.t_opt.kind = TCP_O_TS;
+ b->sack.t_opt.len = TCP_OPT_LEN_A;
+ b->sack.t_opt.t_snd = htons(loc_timestamp);
+ b->sack.t_opt.t_rcv = rmt_timestamp;
+ b->sack.sack_v.kind = TCP_1_NOP;
+ b->sack.sack_v.len = 0x00;
+
+#if defined(CONFIG_PROT_TCP_SACK)
+ if (tcp_lost.len > TCP_OPT_LEN_2) {
+ debug_cond(DEBUG_DEV_PKT, "TCP ack opt lost.len %x\n",
+ tcp_lost.len);
+ b->sack.sack_v.len = tcp_lost.len;
+ b->sack.sack_v.kind = TCP_V_SACK;
+ b->sack.sack_v.hill[0].l = htonl(tcp_lost.hill[0].l);
+ b->sack.sack_v.hill[0].r = htonl(tcp_lost.hill[0].r);
+
+ /*
+ * These SACK structures are initialized with NOPs to
+ * provide TCP header alignment padding. There are 4
+ * SACK structures used for both header padding and
+ * internally.
+ */
+
+ b->sack.sack_v.hill[1].l = htonl(tcp_lost.hill[1].l);
+ b->sack.sack_v.hill[1].r = htonl(tcp_lost.hill[1].r);
+ b->sack.sack_v.hill[2].l = htonl(tcp_lost.hill[2].l);
+ b->sack.sack_v.hill[2].r = htonl(tcp_lost.hill[2].r);
+ b->sack.sack_v.hill[3].l = TCP_O_NOP;
+ b->sack.sack_v.hill[3].r = TCP_O_NOP;
+ }
+
+ /*
+ * TCP lengths are stored as a rounded up number of 32 bit words
+ * Add 3 to length round up, rounded, then divided into the length
+ * in 32 bit words.
+ */
+
+ b->sack.hdr.tcp_hlen = (((TCP_HDR_SIZE + TCP_TSOPT_SIZE
+ + tcp_lost.len + 3) >> 2) << 4);
+
+#else
+ b->sack.sack_v.kind = 0x00;
+ b->sack.hdr.tcp_hlen = (((TCP_HDR_SIZE + TCP_TSOPT_SIZE
+ + 3) >> 2) << 4);
+#endif
+ /*
+ * This returns the actual rounded up length of the
+ * TCP header to add to the total packet length
+ */
+
+ return b->sack.hdr.tcp_hlen >> 2;
+}
+
+void net_set_syn_options(union tcp_build_pkt *b)
+{
+ tcp_lost.len = 0;
+ b->ip.hdr.tcp_hlen = 0xa0;
+
+ b->ip.mss.kind = TCP_O_MSS;
+ b->ip.mss.len = TCP_OPT_LEN_4;
+ b->ip.mss.mss = htons(TCP_MSS);
+ b->ip.scale.kind = TCP_O_SCL;
+ b->ip.scale.scale = TCP_SCALE;
+ b->ip.scale.len = TCP_OPT_LEN_3;
+#if defined(CONFIG_PROT_TCP_SACK)
+ b->ip.sack_p.kind = TCP_P_SACK;
+ b->ip.sack_p.len = TCP_OPT_LEN_2;
+#else
+ b->ip.sack_p.kind = TCP_1_NOP;
+ b->ip.sack_p.len = TCP_1_NOP;
+#endif
+ b->ip.t_opt.kind = TCP_O_TS;
+ b->ip.t_opt.len = TCP_OPT_LEN_A;
+ loc_timestamp = get_ticks();
+ rmt_timestamp = 0x00000000;
+ b->ip.t_opt.t_snd = 0;
+ b->ip.t_opt.t_rcv = 0x00000000;
+ b->ip.end = TCP_O_END;
+}
+
+int tcp_set_tcp_header(uchar *pkt, int dport, int sport, int payload_len,
+ u8 action, u32 tcp_seq_num, u32 tcp_ack_num)
+{
+ union tcp_build_pkt *b = (union tcp_build_pkt *)pkt;
+ int pkt_hdr_len;
+ int pkt_len;
+ int tcp_len;
+
+/*
+ * Header: 5 32 bit words. 4 bits TCP header Length, 4 bits reserved options
+ */
+ b->ip.hdr.tcp_flags = action;
+ pkt_hdr_len = IP_TCP_HDR_SIZE;
+ b->ip.hdr.tcp_hlen = 0x50;
+
+ switch (action) {
+ case TCP_SYN:
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP Hdr:SYN (%pI4, %pI4, sq=%d, ak=%d)\n",
+ &net_server_ip, &net_ip,
+ tcp_seq_num, tcp_ack_num);
+ tcp_activity_count = 0;
+ net_set_syn_options(b);
+ tcp_seq_num = 0;
+ tcp_ack_num = 0;
+ pkt_hdr_len = IP_TCP_O_SIZE;
+ if (tcp_state == TCP_SYN_SENT) { /* Too many SYNs */
+ action = TCP_FIN;
+ tcp_state = TCP_FIN_WAIT_1;
+ } else {
+ tcp_state = TCP_SYN_SENT;
+ }
+ break;
+ case TCP_ACK:
+ pkt_hdr_len = IP_HDR_SIZE + net_set_ack_options(b);
+ b->ip.hdr.tcp_flags = action;
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP Hdr:ACK (%pI4, %pI4, s=%d, a=%d, A=%x)\n",
+ &net_server_ip, &net_ip, tcp_seq_num, tcp_ack_num,
+ action);
+ break;
+ case TCP_FIN:
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP Hdr:FIN (%pI4, %pI4, s=%d, a=%d)\n",
+ &net_server_ip, &net_ip, tcp_seq_num, tcp_ack_num);
+ payload_len = 0;
+ pkt_hdr_len = IP_TCP_HDR_SIZE;
+ tcp_state = TCP_FIN_WAIT_1;
+
+ break;
+
+ /* Notify connection closing */
+
+ case (TCP_FIN | TCP_ACK):
+ case ((TCP_FIN | TCP_ACK) | TCP_PUSH):
+ if (tcp_state == TCP_CLOSE_WAIT)
+ tcp_state = TCP_CLOSING;
+ tcp_ack_edge++;
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP Hdr:FIN ACK PSH(%pI4, %pI4, s=%d, a=%d, A=%x)\n",
+ &net_server_ip, &net_ip,
+ tcp_seq_num, tcp_ack_edge, action);
+ /* FALLTHRU */
+ default:
+ pkt_hdr_len = IP_HDR_SIZE + net_set_ack_options(b);
+ b->ip.hdr.tcp_flags = action | TCP_PUSH | TCP_ACK;
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP Hdr:dft (%pI4, %pI4, s=%d, a=%d, A=%x)\n",
+ &net_server_ip, &net_ip,
+ tcp_seq_num, tcp_ack_num, action);
+ }
+
+ pkt_len = pkt_hdr_len + payload_len;
+ tcp_len = pkt_len - IP_HDR_SIZE;
+
+ /* TCP Header */
+ b->ip.hdr.tcp_ack = htonl(tcp_ack_edge);
+ b->ip.hdr.tcp_src = htons(sport);
+ b->ip.hdr.tcp_dst = htons(dport);
+ b->ip.hdr.tcp_seq = htonl(tcp_seq_num);
+ tcp_seq_num = tcp_seq_num + payload_len;
+
+ /*
+ * TCP window size - TCP header variable tcp_win.
+ * Change tcp_win only if you have an understanding of network
+ * overrun, congestion, TCP segment sizes, TCP windows, TCP scale,
+ * queuing theory and packet buffering. If there are too few buffers,
+ * there will be data loss, recovery may work or the sending TCP,
+ * the server, could abort the stream transmission.
+ * MSS is governed by maximum Ethernet frame length.
+ * The number of buffers is governed by the desire to have a queue of
+ * full buffers to be processed at the destination to maximize
+ * throughput. Temporary memory use for the boot phase on modern
+ * SOCs is may not be considered a constraint to buffer space, if
+ * it is, then the u-boot tftp or nfs kernel netboot should be
+ * considered.
+ */
+
+ b->ip.hdr.tcp_win = htons(PKTBUFSRX * TCP_MSS >> TCP_SCALE);
+
+ b->ip.hdr.tcp_xsum = 0x0000;
+ b->ip.hdr.tcp_ugr = 0x0000;
+
+ b->ip.hdr.tcp_xsum = tcp_set_pseudo_header(pkt, net_ip, net_server_ip,
+ tcp_len, pkt_len);
+
+ net_set_ip_header((uchar *)&b->ip, net_server_ip, net_ip,
+ pkt_len, IPPROTO_TCP);
+
+ return pkt_hdr_len;
+}
+
+/*
+ * Selective Acknowledgment (Essential for fast stream transfer)
+ */
+
+void tcp_hole(u32 tcp_seq_num, u32 len, u32 tcp_seq_max)
+{
+ unsigned int idx_sack;
+ unsigned int sack_end = TCP_SACK - 1;
+ unsigned int sack_in;
+ unsigned int hill = 0;
+ enum pkt_state expect = PKT;
+
+ u32 seq = tcp_seq_num - tcp_seq_init;
+ u32 hol_l = tcp_ack_edge - tcp_seq_init;
+ u32 hol_r = 0;
+
+ /* Place new seq number in correct place in receive array */
+
+ if (prev_len == 0)
+ prev_len = len;
+ idx_sack = sack_idx + ((tcp_seq_num - tcp_ack_edge) / prev_len);
+ if (idx_sack < TCP_SACK) {
+ edge_a[idx_sack].se.l = tcp_seq_num;
+ edge_a[idx_sack].se.r = tcp_seq_num + len;
+ edge_a[idx_sack].st = PKT;
+
+/*
+ * The fin (last) packet is not the same length as data packets, and if it's
+ * length is recorded and used for array index calculation, calculation breaks.
+ */
+ if (prev_len < len)
+ prev_len = len;
+ }
+
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP 1 seq %d, edg %d, len %d, sack_idx %d, sack_end %d\n",
+ seq, hol_l, len, sack_idx, sack_end);
+
+ /* Right edge of contiguous stream, is the left edge of first hill */
+
+ hol_l = tcp_seq_num - tcp_seq_init;
+ hol_r = hol_l + len;
+
+ tcp_lost.len = TCP_OPT_LEN_2;
+
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP 1 in %d, seq %d, pkt_l %d, pkt_r %d, sack_idx %d, sack_end %d\n",
+ idx_sack, seq, hol_l, hol_r, sack_idx, sack_end);
+
+ for (sack_in = sack_idx; sack_in < sack_end && hill < TCP_SACK_HILLS;
+ sack_in++) {
+ switch (expect) {
+ case NOPKT:
+ switch (edge_a[sack_in].st) {
+ case NOPKT:
+ debug_cond(DEBUG_INT_STATE, "N");
+ break;
+ case PKT:
+ debug_cond(DEBUG_INT_STATE, "n");
+ tcp_lost.hill[hill].l =
+ edge_a[sack_in].se.l;
+ tcp_lost.hill[hill].r =
+ edge_a[sack_in].se.r;
+ expect = PKT;
+ break;
+ }
+ break;
+ case PKT:
+ switch (edge_a[sack_in].st) {
+ case NOPKT:
+ debug_cond(DEBUG_INT_STATE, "p");
+ if (sack_in > sack_idx &&
+ hill < TCP_SACK_HILLS) {
+ hill++;
+ tcp_lost.len += TCP_OPT_LEN_8;
+ }
+ expect = NOPKT;
+ break;
+ case PKT:
+ debug_cond(DEBUG_INT_STATE, "P");
+
+ if (tcp_ack_edge == edge_a[sack_in].se.l) {
+ tcp_ack_edge = edge_a[sack_in].se.r;
+ edge_a[sack_in].st = NOPKT;
+ sack_idx++;
+ } else {
+ if (hill < TCP_SACK_HILLS)
+ tcp_lost.hill[hill].r =
+ edge_a[sack_in].se.r;
+ if (sack_in == sack_end - 1)
+ tcp_lost.hill[hill].r =
+ edge_a[sack_in].se.r;
+ }
+ break;
+ }
+ break;
+ }
+ }
+ debug_cond(DEBUG_INT_STATE, "\n");
+ if (tcp_lost.len <= TCP_OPT_LEN_2)
+ sack_idx = 0;
+}
+
+void tcp_parse_options(uchar *o, int o_len)
+{
+ struct tcp_t_opt *tsopt;
+ uchar *p = o;
+/*
+ * NOPs are options with a zero length, and thus are special.
+ * All other options have length fields.
+ */
+
+ for (p = o; p < (o + o_len); p = p + p[1]) {
+ if (p[1] != 0) {
+ switch (p[0]) {
+ case TCP_O_END:
+ return; /* Finished processing options */
+ case TCP_O_MSS:
+ case TCP_O_SCL:
+ case TCP_P_SACK:
+ case TCP_V_SACK:
+ break; /* Continue to process options */
+ case TCP_O_TS:
+ tsopt = (struct tcp_t_opt *)p;
+ rmt_timestamp = tsopt->t_snd;
+ return;
+ break;
+ } /* End switch, process optional NOPs */
+
+ if (p[0] == TCP_O_NOP)
+ p++;
+ } else {
+ return; /* Finished processing options */
+ }
+ }
+}
+
+u8 tcp_state_machine(u8 tcp_flags, u32 *tcp_seq_num, int payload_len)
+{
+ u8 tcp_fin = tcp_flags & TCP_FIN;
+ u8 tcp_syn = tcp_flags & TCP_SYN;
+ u8 tcp_rst = tcp_flags & TCP_RST;
+ u8 tcp_push = tcp_flags & TCP_PUSH;
+ u8 tcp_ack = tcp_flags & TCP_ACK;
+ u8 action = TCP_DATA;
+ int i;
+
+ /*
+ * tcp_flags are examined to determine TX action in a given state
+ * tcp_push is interpreted to mean "inform the app"
+ * urg, ece, cer and nonce flags are not supported.
+ *
+ * exe and crw are use to signal and confirm knowledge of congestion.
+ * This TCP only sends a file request and acks. If it generates
+ * congestion, the network is broken.
+ */
+
+ debug_cond(DEBUG_INT_STATE, "TCP STATE ENTRY %x\n", action);
+ if (tcp_rst) {
+ action = TCP_DATA;
+ tcp_state = TCP_CLOSED;
+ net_set_state(NETLOOP_FAIL);
+ debug_cond(DEBUG_INT_STATE, "TCP Reset %x\n", tcp_flags);
+ return TCP_RST;
+ }
+
+ switch (tcp_state) {
+ case TCP_CLOSED:
+ debug_cond(DEBUG_INT_STATE, "TCP CLOSED %x\n", tcp_flags);
+ if (tcp_fin)
+ action = TCP_DATA;
+ if (tcp_syn)
+ action = TCP_RST;
+ if (tcp_ack)
+ action = TCP_DATA;
+ break;
+ case TCP_SYN_SENT:
+ debug_cond(DEBUG_INT_STATE, "TCP_SYN_SENT %x, %d\n",
+ tcp_flags, *tcp_seq_num);
+ if (tcp_fin) {
+ action = action | TCP_PUSH;
+ tcp_state = TCP_CLOSE_WAIT;
+ }
+ if (tcp_syn) {
+ action = action | TCP_ACK | TCP_PUSH;
+ if (tcp_ack) {
+ tcp_seq_init = *tcp_seq_num;
+ *tcp_seq_num = *tcp_seq_num + 1;
+ tcp_seq_max = *tcp_seq_num;
+ tcp_ack_edge = *tcp_seq_num;
+ sack_idx = 0;
+ edge_a[sack_idx].se.l = *tcp_seq_num;
+ edge_a[sack_idx].se.r = *tcp_seq_num;
+ prev_len = 0;
+ tcp_state = TCP_ESTABLISHED;
+ for (i = 0; i < TCP_SACK; i++)
+ edge_a[i].st = NOPKT;
+ }
+ } else {
+ if (tcp_ack)
+ action = TCP_DATA;
+ }
+ break;
+ case TCP_ESTABLISHED:
+ debug_cond(DEBUG_INT_STATE,
+ "TCP_ESTABLISHED %x\n", tcp_flags);
+ if (*tcp_seq_num > tcp_seq_max)
+ tcp_seq_max = *tcp_seq_num;
+ if (payload_len > 0) {
+ tcp_hole(*tcp_seq_num, payload_len, tcp_seq_max);
+ tcp_fin = TCP_DATA; /* cause standalone FIN */
+ }
+
+ if ((tcp_fin) && tcp_lost.len <= TCP_OPT_LEN_2) {
+ action = action | TCP_FIN | TCP_PUSH | TCP_ACK;
+ tcp_state = TCP_CLOSE_WAIT;
+ } else {
+ if (tcp_ack)
+ action = TCP_DATA;
+ }
+ if (tcp_push)
+ action = action | TCP_PUSH;
+ if (tcp_syn)
+ action = TCP_ACK + TCP_RST;
+ break;
+ case TCP_CLOSE_WAIT:
+ debug_cond(DEBUG_INT_STATE, "TCP_CLOSE_WAIT (%x)\n", tcp_flags);
+ action = TCP_DATA; /* Wait for app */
+ break;
+ case TCP_FIN_WAIT_2:
+ debug_cond(DEBUG_INT_STATE, "TCP_FIN_WAIT_2 (%x)\n", tcp_flags);
+ if (tcp_fin)
+ action = TCP_DATA;
+ if (tcp_syn)
+ action = TCP_DATA;
+ if (tcp_ack) {
+ action = TCP_PUSH | TCP_ACK;
+ tcp_state = TCP_CLOSED;
+ puts("\n");
+ }
+ break;
+ case TCP_FIN_WAIT_1:
+ debug_cond(DEBUG_INT_STATE, "TCP_FIN_WAIT_1 (%x)\n", tcp_flags);
+ if (tcp_fin) {
+ action = TCP_ACK | TCP_FIN;
+ tcp_state = TCP_FIN_WAIT_2;
+ }
+ if (tcp_syn)
+ action = TCP_RST;
+ if (tcp_ack) {
+ tcp_state = TCP_CLOSED;
+ tcp_seq_num = tcp_seq_num + 1;
+ }
+ break;
+ case TCP_CLOSING:
+ debug_cond(DEBUG_INT_STATE, "TCP_CLOSING (%x)\n", tcp_flags);
+ if (tcp_fin)
+ action = TCP_DATA;
+ if (tcp_syn)
+ action = TCP_RST;
+ if (tcp_ack) {
+ action = TCP_PUSH;
+ tcp_state = TCP_CLOSED;
+ puts("\n");
+ }
+ break;
+ }
+ return action;
+}
+
+void rxhand_tcp_f(union tcp_build_pkt *b, unsigned int pkt_len)
+{
+ int tcp_len = pkt_len - IP_HDR_SIZE;
+ u16 tcp_rx_xsum = b->ip.hdr.ip_sum;
+ u8 tcp_action = TCP_DATA;
+ u32 tcp_seq_num;
+ u32 tcp_ack_num;
+ struct in_addr action_and_state;
+
+ int tcp_hdr_len;
+ int payload_len;
+
+ /*
+ * Verify IP header
+ */
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP RX in RX Sum (to=%pI4, from=%pI4, len=%d)\n",
+ &b->ip.hdr.ip_src, &b->ip.hdr.ip_dst, pkt_len);
+
+ debug_cond(DEBUG_DEV_PKT,
+ "In__________________________________________\n");
+
+ b->ip.hdr.ip_src = net_server_ip;
+ b->ip.hdr.ip_dst = net_ip;
+ b->ip.hdr.ip_sum = 0x0000;
+ if (tcp_rx_xsum != compute_ip_checksum(b, IP_HDR_SIZE)) {
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP RX IP xSum Error (%pI4, =%pI4, len=%d)\n",
+ &net_ip, &net_server_ip, pkt_len);
+ return;
+ }
+
+ /*
+ * Build pseudo header and verify TCP header
+ */
+ tcp_rx_xsum = b->ip.hdr.tcp_xsum;
+ b->ip.hdr.tcp_xsum = 0x0000;
+ if (tcp_rx_xsum != tcp_set_pseudo_header((uchar *)b, b->ip.hdr.ip_src,
+ b->ip.hdr.ip_dst, tcp_len,
+ pkt_len)) {
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP RX TCP xSum Error (%pI4, %pI4, len=%d)\n",
+ &net_ip, &net_server_ip, tcp_len);
+ return;
+ }
+
+ tcp_hdr_len = (b->ip.hdr.tcp_hlen >> 2);
+ payload_len = tcp_len - tcp_hdr_len;
+
+ if (tcp_hdr_len > TCP_HDR_SIZE)
+ tcp_parse_options((uchar *)b + IP_TCP_HDR_SIZE,
+ tcp_hdr_len - TCP_HDR_SIZE);
+ /*
+ * Incoming sequence and ack numbers are server's view of the numbers.
+ * The app must swap the numbers when responding.
+ */
+
+ tcp_seq_num = ntohl(b->ip.hdr.tcp_seq);
+ tcp_ack_num = ntohl(b->ip.hdr.tcp_ack);
+
+ /* Packets are not ordered. Send to app as received. */
+
+ tcp_action = tcp_state_machine(b->ip.hdr.tcp_flags,
+ &tcp_seq_num, payload_len);
+
+ /*
+ * State-altering command to be sent.
+ * The packet sequence and ack numbers are in the tcp_seq_num
+ * and tcp_ack_num variables. The current packet, its position
+ * in the data stream, is the in the range of those variables.
+ *
+ * In the "application push" invocation, the TCP header with all
+ * its information is pointed to by the packet pointer.
+ *
+ * In the typedef
+ * void rxhand_tcp(uchar *pkt, unsigned int dport,
+ * struct in_addr sip, unsigned int sport,
+ * unsigned int len);
+ * *pkt is the pointer to the payload
+ * dport is used for tcp_seg_num
+ * action_and_state.s_addr is used for TCP state
+ * sport is used for tcp_ack_num (which is unused by the app)
+ * pkt_ length is the payload length.
+ *
+ * TCP_PUSH from the state machine with a payload length of 0 is a
+ * connect or disconnect event
+ */
+
+ tcp_activity_count++;
+ if (tcp_activity_count > TCP_ACTIVITY) {
+ puts("| ");
+ tcp_activity_count = 0;
+ }
+
+ if ((tcp_action & TCP_PUSH) || payload_len > 0) {
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP Notify (action=%x, Seq=%d,Ack=%d,Pay%d)\n",
+ tcp_action, tcp_seq_num, tcp_ack_num, payload_len);
+
+ action_and_state.s_addr = tcp_action;
+ (*tcp_packet_handler) ((uchar *)b + pkt_len - payload_len,
+ tcp_seq_num, action_and_state,
+ tcp_ack_num, payload_len);
+
+ } else if (tcp_action != TCP_DATA) {
+ debug_cond(DEBUG_DEV_PKT,
+ "TCP Action (action=%x,Seq=%d,Ack=%d,Pay=%d)\n",
+ tcp_action, tcp_seq_num, tcp_ack_num, payload_len);
+
+ /*
+ * Warning: Incoming Ack & Seq sequence numbers are transposed
+ * here to outgoing Seq & Ack sequence numbers
+ */
+ net_send_tcp_packet(0, ntohs(b->ip.hdr.tcp_src),
+ ntohs(b->ip.hdr.tcp_dst),
+ (tcp_action & (~TCP_PUSH)),
+ tcp_seq_num, tcp_ack_num);
+ }
+}
--
2.35.1
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