From: "Ying-Chun Liu (PaulLiu)" paul.liu@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@Synoia.com Signed-off-by: Duncan Hare DuncanCHare@yahoo.com Signed-off-by: Ying-Chun Liu (PaulLiu) paul.liu@linaro.org Cc: Christian Gmeiner christian.gmeiner@gmail.com Cc: Joe Hershberger joe.hershberger@ni.com Cc: Michal Simek michal.simek@xilinx.com Cc: Ramon Fried rfried.dev@gmail.com --- v1-v12: Made by Duncan, didn't tracked. v13: Fix some issues which is reviewed by Christian v14: Add options to enable/disable SACK. v15: Fix various syntax errors reviewed by Michal. Remove magic numbers. Use kernel-doc format. v16: Add more kernel-doc. Fix more double spaces. --- include/net.h | 36 ++- include/net/tcp.h | 312 ++++++++++++++++++++ net/Kconfig | 16 ++ net/Makefile | 1 + net/net.c | 30 ++ net/tcp.c | 720 ++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 1106 insertions(+), 9 deletions(-) create mode 100644 include/net/tcp.h create mode 100644 net/tcp.c

diff --git a/include/net.h b/include/net.h index e3889a0bc8..b7bac86cf1 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 */

/* @@ -688,19 +689,36 @@ static inline void net_send_packet(uchar *pkt, int len) (void) eth_send(pkt, len); }

-/* - * Transmit "net_tx_packet" as UDP packet, performing ARP request if needed - * (ether will be populated) - * - * @param ether Raw packet buffer - * @param dest IP address to send the datagram to - * @param dport Destination UDP port - * @param sport Source UDP port - * @param payload_len Length of data after the UDP header +/** + * net_send_ip_packet() - Transmit "net_tx_packet" as UDP or TCP packet, + * send ARP request if needed (ether will be populated) + * @ether: Raw packet buffer + * @dest: IP address to send the datagram to + * @dport: Destination UDP port + * @sport: Source UDP port + * @payload_len: Length of data after the UDP header + * @action: TCP action to be performed + * @tcp_seq_num: TCP sequence number of this transmission + * @tcp_ack_num: TCP stream acknolegement number + * + * Return: 0 on success, other value on failure */ 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); +/** + * net_send_tcp_packet() - Transmit TCP packet. + * @payload_len: length of payload + * @dport: Destination TCP port + * @sport: Source TCP port + * @action: TCP action to be performed + * @tcp_seq_num: TCP sequence number of this transmission + * @tcp_ack_num: TCP stream acknolegement number + * + * Return: 0 on success, other value on failure + */ +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..9c97f2f315 --- /dev/null +++ b/include/net/tcp.h @@ -0,0 +1,312 @@ +/* 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 - IP and TCP header + * @ip_hl_v: header length and version + * @ip_tos: type of service + * @ip_len: total length + * @ip_id: identification + * @ip_off: fragment offset field + * @ip_ttl: time to live + * @ip_p: protocol + * @ip_sum: checksum + * @ip_src: Source IP address + * @ip_dst: Destination IP address + * @tcp_src: TCP source port + * @tcp_dst: TCP destination port + * @tcp_seq: TCP sequence number + * @tcp_ack: TCP Acknowledgment number + * @tcp_hlen: 4 bits TCP header Length/4, 4 bits reserved, 2 more bits reserved + * @tcp_flag: flags of TCP + * @tcp_win: TCP windows size + * @tcp_xsum: Checksum + * @tcp_ugr: Pointer to urgent data + */ +struct ip_tcp_hdr { + u8 ip_hl_v; + u8 ip_tos; + u16 ip_len; + u16 ip_id; + u16 ip_off; + u8 ip_ttl; + u8 ip_p; + u16 ip_sum; + struct in_addr ip_src; + struct in_addr ip_dst; + u16 tcp_src; + u16 tcp_dst; + u32 tcp_seq; + u32 tcp_ack; + u8 tcp_hlen; + u8 tcp_flags; + u16 tcp_win; + u16 tcp_xsum; + u16 tcp_ugr; +} __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 */ +#define TCP_MSS 1460 /* Max segment size */ +#define TCP_SCALE 0x01 /* Scale */ + +/** + * struct tcp_mss - TCP option structure for MSS (Max segment size) + * @kind: Field ID + * @len: Field length + * @mss: Segment size value + */ +struct tcp_mss { + u8 kind; + u8 len; + u16 mss; +} __packed; + +/** + * struct tcp_scale - TCP option structure for Windows scale + * @kind: Field ID + * @len: Field length + * @scale: windows shift value used for networks with many hops. + * Typically 4 or more hops + */ +struct tcp_scale { + u8 kind; + u8 len; + u8 scale; +} __packed; + +/** + * struct tcp_sack_p - TCP option structure for SACK permitted + * @kind: Field ID + * @len: Field length + */ +struct tcp_sack_p { + u8 kind; + u8 len; +} __packed; + +/** + * struct sack_edges - structure for SACK edges + * @l: Left edge of stream + * @r: right edge of stream + */ +struct sack_edges { + u32 l; + u32 r; +} __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 - TCP option structure for SACK + * @kind: Field ID + * @len: Field length + * @hill: L & R window edges + */ +struct tcp_sack_v { + u8 kind; + u8 len; + struct sack_edges hill[TCP_SACK_HILLS]; +} __packed; + +/** + * struct tcp_t_opt - TCP option structure for time stamps + * @kind: Field ID + * @len: Field length + * @t_snd: Sender timestamp + * @t_rcv: Receiver timestamp + */ +struct tcp_t_opt { + u8 kind; + u8 len; + u32 t_snd; + u32 t_rcv; +} __packed; + +#define TCP_TSOPT_SIZE (sizeof(struct tcp_t_opt)) + +/* + * ip tcp structure with options + */ + +/** + * struct ip_tcp_hdr_o - IP + TCP header + TCP options + * @hdr: IP + TCP header + * @mss: TCP MSS Option + * @scale: TCP Windows Scale Option + * @sack_p: TCP Sack-Permitted Option + * @t_opt: TCP Timestamp Option + * @end: end of 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 - IP + TCP header + TCP options + * @hdr: IP + TCP header + * @t_opt: TCP Timestamp Option + * @sack_v: TCP SACK Option + * @end: end of options + */ +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 - Pseudo Header + * @padding: pseudo hdr size = ip_tcp hdr size + * @p_src: Source IP address + * @p_dst: Destination IP address + * @rsvd: reserved + * @p: protocol + * @len: length of header + */ +struct pseudo_hdr { + u8 padding[PSEUDO_PAD_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 tcp_build_pkt - union for building TCP/IP packet. + * @ph: pseudo header + * @ip: IP and TCP header plus TCP options + * @sack: IP and TCP header plus SACK options + * @raw: buffer + * + * 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; + +/** + * enum tcp_state - TCP State machine states for connection + * @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_CLOSED, + TCP_SYN_SENT, + TCP_ESTABLISHED, + TCP_CLOSE_WAIT, + TCP_CLOSING, + TCP_FIN_WAIT_1, + TCP_FIN_WAIT_2 +}; + +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); + +/** + * rxhand_tcp() - An incoming packet handler. + * @pkt: pointer to the application packet + * @dport: destination UDP port + * @sip: source IP address + * @sport: source UDP port + * @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); + +/** + * rxhand_action() - An incoming TCP packet handler for the TCP protocol. + * @tcp_action: Actions of TCP + * @payload_len: Payload length + * @tcp_seq_num: TCP sequence number + * @tcp_ack_num: TCP acknowledge number + * @pkt_len: Packet length + * @b: TCP packet + * + * 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 964a4fe499..0835d1904f 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -168,6 +168,22 @@ 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" + depends on PROT_TCP + help + TCP protocol with SACK. SACK means selective acknowledgements. + By turning this option on TCP will learn what segments are already + received. So that it improves TCP's retransmission efficiency. + This option should be turn on if you want to achieve the fastest + file transfer possible. + endif # if NET

config SYS_RX_ETH_BUFFER diff --git a/net/Makefile b/net/Makefile index 6c812502d3..d131d1cb1a 100644 --- a/net/Makefile +++ b/net/Makefile @@ -30,6 +30,7 @@ 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 81905f6315..751d0251be 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; } @@ -1256,6 +1277,15 @@ 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..8d338c72e8 --- /dev/null +++ b/net/tcp.c @@ -0,0 +1,720 @@ +// 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; + +static u32 tcp_seq_init; +static u32 tcp_ack_edge; +static u32 tcp_seq_max; + +static 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; +}; + +static struct sack_r edge_a[TCP_SACK]; +static unsigned int sack_idx; +static unsigned int prev_len; + +/* + * 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. + */ +#define LEN_B_TO_DW(x) ((x) >> 2) +#define ROUND_TCPHDR_LEN(x) (LEN_B_TO_DW((x) + 3)) +#define SHIFT_TO_TCPHDRLEN_FIELD(x) ((x) << 4) +#define GET_TCP_HDR_LEN_IN_BYTES(x) ((x) >> 2) + +/* TCP connection state */ +static enum tcp_state current_tcp_state; + +/* Current TCP RX packet handler */ +static rxhand_tcp *tcp_packet_handler; + +/** + * tcp_get_tcp_state() - get current TCP state + * + * Return: Current TCP state + */ +enum tcp_state tcp_get_tcp_state(void) +{ + return current_tcp_state; +} + +/** + * tcp_set_tcp_state() - set current TCP state + * @new_state: new TCP state + */ +void tcp_set_tcp_state(enum tcp_state new_state) +{ + current_tcp_state = new_state; +} + +static void dummy_handler(uchar *pkt, unsigned int dport, + struct in_addr sip, unsigned int sport, + unsigned int len) +{ +} + +/** + * tcp_set_tcp_handler() - set a handler to receive data + * @f: handler + */ +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; +} + +/** + * tcp_set_pseudo_header() - set TCP pseudo header + * @pkt: the packet + * @src: source IP address + * @dest: destinaion IP address + * @tcp_len: tcp length + * @pkt_len: packet length + * + * Return: the checksum of the packet + */ +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] = 0; + + net_copy_ip((void *)&b->ph.p_src, &src); + net_copy_ip((void *)&b->ph.p_dst, &dest); + b->ph.rsvd = 0; + 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); +} + +/** + * net_set_ack_options() - set TCP options in acknowledge packets + * @b: the packet + * + * Return: TCP header length + */ +int net_set_ack_options(union tcp_build_pkt *b) +{ + b->sack.hdr.tcp_hlen = SHIFT_TO_TCPHDRLEN_FIELD(LEN_B_TO_DW(TCP_HDR_SIZE)); + + 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 = 0; + + if (IS_ENABLED(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; + } + + b->sack.hdr.tcp_hlen = SHIFT_TO_TCPHDRLEN_FIELD(ROUND_TCPHDR_LEN(TCP_HDR_SIZE + + TCP_TSOPT_SIZE + + tcp_lost.len)); + } else { + b->sack.sack_v.kind = 0; + b->sack.hdr.tcp_hlen = SHIFT_TO_TCPHDRLEN_FIELD(ROUND_TCPHDR_LEN(TCP_HDR_SIZE + + TCP_TSOPT_SIZE)); + } + + /* + * This returns the actual rounded up length of the + * TCP header to add to the total packet length + */ + + return GET_TCP_HDR_LEN_IN_BYTES(b->sack.hdr.tcp_hlen); +} + +/** + * net_set_ack_options() - set TCP options in SYN packets + * @b: the packet + */ +void net_set_syn_options(union tcp_build_pkt *b) +{ + if (IS_ENABLED(CONFIG_PROT_TCP_SACK)) + 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 (IS_ENABLED(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; + } + b->ip.t_opt.kind = TCP_O_TS; + b->ip.t_opt.len = TCP_OPT_LEN_A; + loc_timestamp = get_ticks(); + rmt_timestamp = 0; + b->ip.t_opt.t_snd = 0; + b->ip.t_opt.t_rcv = 0; + 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 = SHIFT_TO_TCPHDRLEN_FIELD(LEN_B_TO_DW(TCP_HDR_SIZE)); + + 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 (current_tcp_state == TCP_SYN_SENT) { /* Too many SYNs */ + action = TCP_FIN; + current_tcp_state = TCP_FIN_WAIT_1; + } else { + current_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; + current_tcp_state = TCP_FIN_WAIT_1; + break; + + /* Notify connection closing */ + + case (TCP_FIN | TCP_ACK): + case (TCP_FIN | TCP_ACK | TCP_PUSH): + if (current_tcp_state == TCP_CLOSE_WAIT) + current_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); + fallthrough; + 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 = 0; + b->ip.hdr.tcp_ugr = 0; + + 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; +} + +/** + * tcp_hole() - Selective Acknowledgment (Essential for fast stream transfer) + * @tcp_seq_num: TCP sequence start number + * @len: the length of sequence numbers + * @tcp_seq_max: maximum of sequence numbers + */ +void tcp_hole(u32 tcp_seq_num, u32 len, u32 tcp_seq_max) +{ + u32 idx_sack, sack_in; + u32 sack_end = TCP_SACK - 1; + u32 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; + + if (IS_ENABLED(CONFIG_PROT_TCP_SACK)) + 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"); + if (IS_ENABLED(CONFIG_PROT_TCP_SACK)) { + 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++; + if (IS_ENABLED(CONFIG_PROT_TCP_SACK)) + 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 (IS_ENABLED(CONFIG_PROT_TCP_SACK) && + hill < TCP_SACK_HILLS) + tcp_lost.hill[hill].r = + edge_a[sack_in].se.r; + if (IS_ENABLED(CONFIG_PROT_TCP_SACK) && + 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 (!IS_ENABLED(CONFIG_PROT_TCP_SACK) || tcp_lost.len <= TCP_OPT_LEN_2) + sack_idx = 0; +} + +/** + * tcp_parse_options() - parsing TCP options + * @o: pointer to the option field. + * @o_len: length of the option field. + */ +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]) + return; /* Finished processing options */ + + switch (p[0]) { + case TCP_O_END: + return; + case TCP_O_MSS: + case TCP_O_SCL: + case TCP_P_SACK: + case TCP_V_SACK: + break; + case TCP_O_TS: + tsopt = (struct tcp_t_opt *)p; + rmt_timestamp = tsopt->t_snd; + return; + } + + /* Process optional NOPs */ + if (p[0] == TCP_O_NOP) + p++; + } +} + +static 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; + current_tcp_state = TCP_CLOSED; + net_set_state(NETLOOP_FAIL); + debug_cond(DEBUG_INT_STATE, "TCP Reset %x\n", tcp_flags); + return TCP_RST; + } + + switch (current_tcp_state) { + case TCP_CLOSED: + debug_cond(DEBUG_INT_STATE, "TCP CLOSED %x\n", tcp_flags); + if (tcp_ack) + action = TCP_DATA; + else if (tcp_syn) + action = TCP_RST; + else if (tcp_fin) + 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; + current_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; + current_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) && + (!IS_ENABLED(CONFIG_PROT_TCP_SACK) || + tcp_lost.len <= TCP_OPT_LEN_2)) { + action = action | TCP_FIN | TCP_PUSH | TCP_ACK; + current_tcp_state = TCP_CLOSE_WAIT; + } else if (tcp_ack) { + action = TCP_DATA; + } + + if (tcp_syn) + action = TCP_ACK + TCP_RST; + else if (tcp_push) + action = action | TCP_PUSH; + break; + case TCP_CLOSE_WAIT: + debug_cond(DEBUG_INT_STATE, "TCP_CLOSE_WAIT (%x)\n", tcp_flags); + action = TCP_DATA; + break; + case TCP_FIN_WAIT_2: + debug_cond(DEBUG_INT_STATE, "TCP_FIN_WAIT_2 (%x)\n", tcp_flags); + if (tcp_ack) { + action = TCP_PUSH | TCP_ACK; + current_tcp_state = TCP_CLOSED; + puts("\n"); + } else if (tcp_syn) { + action = TCP_DATA; + } else if (tcp_fin) { + action = TCP_DATA; + } + 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; + current_tcp_state = TCP_FIN_WAIT_2; + } + if (tcp_syn) + action = TCP_RST; + if (tcp_ack) { + current_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_ack) { + action = TCP_PUSH; + current_tcp_state = TCP_CLOSED; + puts("\n"); + } else if (tcp_syn) { + action = TCP_RST; + } else if (tcp_fin) { + action = TCP_DATA; + } + break; + } + return action; +} + +/** + * rxhand_tcp_f() - process receiving data and call data handler. + * @b: the packet + * @pkt_len: the length of packet. + */ +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, tcp_ack_num; + struct in_addr action_and_state; + int tcp_hdr_len, 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); + + b->ip.hdr.ip_src = net_server_ip; + b->ip.hdr.ip_dst = net_ip; + b->ip.hdr.ip_sum = 0; + 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 = 0; + 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 = GET_TCP_HDR_LEN_IN_BYTES(b->ip.hdr.tcp_hlen); + 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); + + 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); + } +}