[U-Boot] [PATCH 2/3] TCP code. All is new.
Joe Hershberger
joe.hershberger at ni.com
Mon Feb 26 23:08:05 UTC 2018
-On Sat, Feb 24, 2018 at 4:41 PM, <DH at synoia.com> wrote:
> From: Duncan Hare <DuncanCHare at yahoo.com>
>
> Passed through patman, which does not like packed headers. But, packed
> headers are a requirement to meet protocol header standards.
This should be in a notes section for patman. It is acceptable to
ignore that checkpatch warning about packed structs.
>
> Signed-off-by: Duncan Hare <DuncanCHare at yahoo.com>
> ---
>
> net/Makefile | 3 +-
> net/tcp.c | 723 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> net/tcp.h | 219 ++++++++++++++++++
How about moving this to include/net/tcp.h?
> 3 files changed, 944 insertions(+), 1 deletion(-)
> create mode 100644 net/tcp.c
> create mode 100644 net/tcp.h
>
> diff --git a/net/Makefile b/net/Makefile
> index ae54eee5af..f83df5b728 100644
> --- a/net/Makefile
> +++ b/net/Makefile
> @@ -25,7 +25,8 @@ obj-$(CONFIG_CMD_PING) += ping.o
> obj-$(CONFIG_CMD_RARP) += rarp.o
> obj-$(CONFIG_CMD_SNTP) += sntp.o
> obj-$(CONFIG_CMD_NET) += tftp.o
> -
> +obj-$(CONFIG_TCP) += tcp.o
> +obj-$(CONFIG_CMD_WGET) += wget.o
Don't enable the wget build in this patch.
> # Disable this warning as it is triggered by:
> # sprintf(buf, index ? "foo%d" : "foo", index)
> # and this is intentional usage.
> diff --git a/net/tcp.c b/net/tcp.c
> new file mode 100644
> index 0000000000..22f43e110c
> --- /dev/null
> +++ b/net/tcp.c
> @@ -0,0 +1,723 @@
> +/*
> + * Copyright 2017 Duncan Hare, all rights reserved.
Please also include a SPDX-License-Identifier:.
> + */
> +
> +/*
> + * General Desription:
> + *
> + * TCP support for the wget command, for fast file downloading.
> + *
> + * HTTP/TCP Receiver:
> + *
> + * Prequeisites: - own ethernet address
> + * - own IP address
> + * - Server IP address
> + * - HTP client
Huh? Typo at least - maybe you mean server here? Unclear.
> + * - Bootfile path & name
It would be better if you referenced literal U-Boot variables that
need to be populated instead of loose naming of them.
> + * We want: - Load the Boot file
Seems like something that would happen only with wget. Maybe this
should be moved there.
> + * Next Step HTTPS?
> + */
> +#include <common.h>
> +#include <command.h>
> +#include <console.h>
> +#include <environment.h>
> +#include <errno.h>
> +#include <net.h>
> +#include "tcp.h"
When moved, this could instead be #include <net/tcp.h>
> +#include "wget.h"
This doesn't exist yet.
> +
> +/* TCP sliding window control */
> +/* used by us to request re-TX */
Please use multi-line comment format:
/*
* my comment...
* continued
*/
> +
> +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
Please use an empty /* line to begin a multi-line comment.
> + * 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 dymanic function pointer for TCP based commads 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;
> +}
> +
> +void tcp_print_buffer(uchar raw[], int pkt_len, int payload_len,
> + int hdr_len, bool hide)
Should this function only be available with a debug flag?
> +{
> + int i;
> +
> + for (i = pkt_len - payload_len; i < pkt_len; i++) {
> + if (i <= hdr_len)
> + printf("%02X", raw[i]);
> + else if ((raw[i] > 0x19) && (raw[i] < 0x7f))
> + putc(raw[i]);
> + else if (hide == 0)
> + putc(raw[i]);
> + else
> + printf("%02X", raw[i]);
> + }
> + printf("%s", "\n");
> +}
> +
> +int tcp_find_in_buffer(uchar raw[], int payload_len, uchar field[],
> + int field_len)
> +{
> + int i, j;
> +
> + for (i = 0; i < payload_len; i++) {
> + if (raw[i] == field[0]) {
> + for (j = 1; j < field_len; j++) {
> + if (raw[i + j] != field[j])
> + break;
> + if (j == field_len)
> + return i;
> + }
> + }
> + }
> + return 0;
> +}
> +
> +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,
Bad indent level.
> + "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;
Please add a comment about the alignment you are trying to achieve.
> +
> + 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 = 0x01;
> + b->sack.sack_v.len = 0x00;
> +
> + 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 = (((TCP_HDR_SIZE + TCP_TSOPT_SIZE
> + + tcp_lost.len + 3) >> 2) << 4);
> + 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;
> + b->ip.sack_p.kind = TCP_P_SACK;
> + b->ip.sack_p.len = TCP_OPT_LEN_2;
> + b->ip.t_opt.kind = TCP_O_TS;
> + b->ip.t_opt.len = TCP_OPT_LEN_A;
> + loc_timestamp = get_ticks() % 3072;
> + 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;
> +
> + b->ip.hdr.tcp_flags = action;
> + pkt_hdr_len = IP_TCP_HDR_SIZE;
> + b->ip.hdr.tcp_hlen = 0x50; /* Header is 5 32 bit words */
> + /* 4 bits TCP header Length/4*/
> + /* 4 bits Reserved */
> + /* For options */
> + 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 sins */
> + 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 */
Why is this comment on the same like as the break? How does break
accomplish this?
> + 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 */
Indent this the same as the default: label.
> + 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
> + */
Use single-line comment.
> + 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
> + * overruun, congestion, TCP segment sizes, TCP windows, TCP scale,
overruun -> overrun
> + * 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 langth.
langth -> 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
thEn -> then
> + * 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);
> +
> + /*
> + * IP Header
> + */
> +
> + 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)
> + *
> + * Before modifying theis section of code, which the author found difficult
theis -> this
> + * to write, please be familiar with the SACK (Selective Acknowledgment) RFCs.
> + */
> +
> +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;
Use a single space between hill and =.
> + 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 seq number in correct place */
> +
> + 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 lanegth as data packets,
lanegth -> length
> + * and if it's length is recorded ad used for array index
ad -> and
> + * the arrary index calculations break.
arrary -> array
> + */
Fix indentation of this comment block.
> + 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);
Parenthesis around these conditions are not needed.
> + 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;
> +
> + for (p = o; p < (o + o_len); p = p + p[1]) {
> + if (p[1] != 0) {
> + switch (p[0]) {
> + case TCP_O_END:
> + return;
> + case TCP_O_MSS:
> + break;
> + case TCP_O_SCL:
> + break;
> + case TCP_P_SACK:
> + break;
> + case TCP_V_SACK:
> + break;
> + case TCP_O_TS:
> + tsopt = (struct tcp_t_opt *)p;
> + rmt_timestamp = tsopt->t_snd;
> + return;
> + break;
> + }
> + if (p[0] == TCP_O_NOP)
> + p++;
> + } else {
> + return; }
Put the closing brace on its own line.
> + }
> +}
> +
> +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 intrepreted to mean "inform the app"
intrepreted -> interpreted
> + * 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
ip -> IP
> + */
> + 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 xum Error (%pI4, =%pI4, len=%d)\n",
xum -> xSum
> + &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);
> +
> + /*
> + * Send first packet send from server as first to app
send -> sent
> + * Other packets could be ordered, but are currently not ordered.
> + */
> +
> + 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 date stream, is the in the range of those variables.
date -> data
> + *
> + * In the "application push" invocation the TCP header with all
invocation,
> + * its information is pointed to by the packet pointer, and the
> + * other variable "repurposed" (or misused) to carry sequence numbers
What other variable. Call it out explicitly.
> + * and TCP state.
> + *
> + * 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 Seq & Ack sequence numbers are transposed here
> + * to outgoing Seq & Ack sequence numbers
> + */
Fix indentation.
> +
Remove this blank line.
> + 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);
> + }
> +}
> diff --git a/net/tcp.h b/net/tcp.h
> new file mode 100644
> index 0000000000..4d50390c6d
> --- /dev/null
> +++ b/net/tcp.h
> @@ -0,0 +1,219 @@
> +/*
> + * TCP Support for file transfer.
> + *
> + * Copyright 2017 Duncan Hare, All rights reserved.
Include a SPDX-License-Identifier.
> + *
> + * History
> + * 10/2017 Initial code
Git already keeps the history - drop this section.
> + */
> +
> +#define TCP_ACTIVITY 127 /* Activity on down loading */
down loading -> downloading
> +
> +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 /* Timestanp option */
Timestanp -> Timestamp
> +#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 reviw the warning in net.c about these two paraeters.
reviw -> review , paraeters ->parameters
> + * They are part of a promise of RX buffer size to the sending TCP
> + */
> +
> +#define TCP_MSS 1460 /* Max segment size - 1460 */
> +#define TCP_SCALE 0x01 /* Scale 1 */
> +
> +struct tcp_mss { /* TCP Mex Segment size */
> + u8 kind; /* 0x02 */
> + u8 len; /* 0x04 */
> + u16 mss; /* 1460 - Max segment size */
> +} __packed;
> +
> +struct tcp_scale { /* TCP Windows Scale */
> + u8 kind; /* 0x03 */
> + u8 len; /* 0x03 */
> + u8 scale; /* win shift fat fast networks */
fat -> for?
> +} __packed;
> +
> +struct tcp_sack_p { /* SACK permitted */
> + u8 kind; /* 0x04 */
> + u8 len; /* Length */
> +} __packed;
> +
> +struct sack_edges {
> + u32 l;
> + u32 r;
> +} __packed;
> +
> +#define TCP_SACK_SIZE (sizeof(struct sack_edges))
> +
> +#define TCP_SACK_HILLS 4
> +
> +struct tcp_sack_v {
> + u8 kind; /* 0x05 */
> + u8 len; /* Length */
> + struct sack_edges hill[TCP_SACK_HILLS]; /* L & R widow edges */
> +} __packed;
> +
> +struct tcp_t_opt { /* TCP time stamps option */
> + u8 kind; /* 0x08 */
> + u8 len; /* 0x0a */
> + 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 IP/TCP packet.
> + * build Pseudo header in packed bufferfirst, calculate TCP checksum
bufferfirst -> buffer first
> + * then build IP header in packe buffer.
packe -> packed
> + */
> +
> +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 SOCKET
> + */
> +
> +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, /* Sendt FIN waiting for response */
Sendt -> Sent
> + TCP_FIN_WAIT_2 /* Rec ACK from FIN sent, waitng for FIN */
waitng -> waiting
> +};
> +
> +int tcp_find_in_buffer(uchar raw[], int payload_len, uchar field[],
> + int field_len);
> +void tcp_print_buffer(uchar raw[], int pkt_len, int payload_len,
> + int hdr_len, bool hide);
> +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 dymanic function pointer for TCP based commads to
dymanic -> dynamic , commads -> commands
> + * 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);
> --
> 2.11.0
>
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