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Commit 088b000

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update cs144lab
1 parent 5321e94 commit 088b000

10 files changed

Lines changed: 156 additions & 25 deletions

‎.DS_Store‎

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‎Notes/C++.md‎

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33
#### debug
44
[macOS上用VSCode](https://zhuanlan.zhihu.com/p/106935263?utm_source=wechat_session)
55

6-
[lldb的使用](https://www.jianshu.com/p/9a71329d5c4d)
7-
* breakpoint set -n main, run, print, next
6+
* [CS107 GDB and Debugging教程](https://web.stanford.edu/class/archive/cs/cs107/cs107.1202/resources/gdb)
7+
* [CS107 Software Testing Strategies](https://web.stanford.edu/class/archive/cs/cs107/cs107.1202/testing.html)
8+
9+
* [lldb的使用](https://www.jianshu.com/p/9a71329d5c4d)
10+
* breakpoint set -n main, run, print, next
11+
* 内存泄露问题
12+
* `cmake .. -DCMAKE_BUILD_TYPE=RelASan`
13+
* `valgrind`
14+
* `cmake .. -DCMAKE_BUILD_TYPE=Debug` + `gdb`
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#### C
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@@ -57,6 +64,10 @@ public:
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```
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* 类的静态成员函数指针
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#### 编程习惯
68+
RAII原则:Resource acquisition is initialization
69+
* [CppCoreGuidelines](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md)
70+
* 用[CppCheck](http://cppcheck.net/)诊断,`make cppcheck`
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#### 输入输出
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@@ -104,7 +115,7 @@ sort,自己定义cmp函数,注意cmp的定义:类内静态,传参引用
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##### \<deque>
107-
* deque,两端都能进出,双向队列
118+
* deque,两端都能进出,双向队列,[用法详解](https://blog.csdn.net/u011630575/article/details/79923132)
108119
* [STL之deque实现详解]( https://blog.csdn.net/u010710458/article/details/79540505?depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromBaidu-6&utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromBaidu-6)
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* deque的pop_front相当于queue的pop()
110121

‎Notes/Computer-Networking-Lab-CS144-Stanford.md‎

Lines changed: 33 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -124,7 +124,38 @@ void get_URL(const string &host, const string &path) {
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* <img src="Computer-Networking-Lab-CS144-Stanford/reassembler.png" alt="reassembler" style="zoom:100%;" />
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126126
#### lab2: the TCP receiver
127-
#####
127+
##### 3.1 Sequence Numbers
128+
129+
<img src="Computer-Networking-Lab-CS144-Stanford/001.jpg" alt="different index" style="zoom:100%;" />
130+
* 利用头文件中的函数简化代码
131+
* 计算出相对checkpoint的偏移量之后,再转化成离checkpoint最近的点,如果加多了就左移,注意返回值太小无法左移的情形。
132+
133+
```c++
134+
uint64_t unwrap(WrappingInt32 n, WrappingInt32 isn, uint64_t checkpoint) {
135+
uint32_t offset = n - wrap(checkpoint, isn);
136+
uint64_t ret = checkpoint + offset;
137+
// 取距离checkpoint最近的值,因此判断的情况是否左移ret
138+
//注意位置不够左移的情形!!!
139+
if (offset >= (1u << 31) && ret >= UINT32_LEN)
140+
ret -= (1ul << 32);
141+
return ret;
142+
}
143+
```
144+
##### 3.2 window
145+
* lower:ackno
146+
* higher~window size
147+
* window size = capacity - ByteStream.buffer_size()
148+
149+
##### 3.3 TCP receiver的实现
150+
1. receive segmentsfrom its peer
151+
2. reassemble the ByteStream using your StreamReassembler, and calculate the
152+
3. acknowledgment number (ackno)
153+
4. and the window size.
154+
155+
* `_reassembler`忽视SYN,所以要手动对index减1、ackno()加1
156+
* 非常规路线的处理:比如对于第二个SYN或者FIN信号,接收机选择忽视,具体见`bool TCPReceiver::segment_received(const TCPSegment &seg)`的实现
157+
158+
128159
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#### 工程细节
@@ -140,7 +171,6 @@ string d(size, 0);
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generate(d.begin(), d.end(), [&] { return rd(); });
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```
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143-
144174
* 类cmp函数的定义,适用 `lower_bound()`方法
145175
* 两个**const**都不能掉!
146176
```c++
@@ -152,3 +182,4 @@ class typeUnassembled {
152182
bool operator<(const typeUnassembled &t1) const { return index < t1.index; }
153183
};
154184
```
185+
* `urg = static_cast<bool>(fl_b & 0b0010'0000); // binary literals and ' digit separator since C++14!!!`
76.7 KB
Loading[フレーム]

‎Notes/Computer-Networking-Lecture-CS144-Stanford.md‎

Lines changed: 37 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -336,7 +336,9 @@ end-to-end check
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<img src="Computer-Networking-Lecture-CS144-Stanford/013.jpg" alt="TCP Connection" style="zoom:100%;" />
338338

339-
##### 2-7 Flow Control: Stop-and-Wait
339+
* 非常规路线的处理:比如对于第二个SYN或者FIN信号,接收机选择忽视,具体见`bool TCPReceiver::segment_received(const TCPSegment &seg)`的实现
340+
341+
##### 2-7 Flow Control I: Stop-and-Wait
340342
* 核心是receiver给sender反馈,让sender不要送太多packets
341343
* 基本方法
342344
* stop and wait
@@ -351,8 +353,40 @@ end-to-end check
351353
<img src="Computer-Networking-Lecture-CS144-Stanford/014.jpg" alt="stop-and-wait" style="zoom:100%;" />
352354

353355
##### 2-7 Flow Control II: Sliding Window
354-
355-
356+
* Stop-and-Wait的性能:RTT=50ms, Bottleneck=10Mbps, Ethernet packet length=12Kb => 性能(2%)远远不到瓶颈
357+
* Sliding Window计算Window size填满性能
358+
359+
**Sliding Window Sender**
360+
361+
* Every segment has a sequence number (SeqNo)
362+
* Maintain 3 variables
363+
* Send window size(SWS)
364+
* Last acknowledgment(LAR)
365+
* Last segment sent(LSS)
366+
* Maintain invariant: $(LSS - LAR) \leq SWS$
367+
* Advance LAR on new acknowledgement
368+
* Buffer up to SWS segments
369+
370+
**Sliding Window Receiver**
371+
* Maintain 3 variables
372+
* Receive window size(RWS)
373+
* Last acceptable segment(LAS)
374+
* Last segment received(LSR)
375+
* Maintain invariant: $(LAS - LSR) \leq RWS$
376+
* 如果收到的packet比LAS小,则发送ack
377+
* 发送cumulative acks: 收到1, 2, 3, 5,发送3
378+
* TCP acks are next expected data,因此要加一,上个例子改为4,初值为0
379+
380+
**RWS, SWS, and Sequence Space**
381+
* $RWS \geq 1, SWS \geq 1, RWS \leq SWS$
382+
* if $RWS = 1,ドル "go back N" protocol ,need SWS+1 sequence numbers (需要多重传)
383+
* if $RWS = SWS,ドル need 2SWS sequence numbers
384+
* 通常需要$RWS+SWS$ sequence numbers:考虑临界情况,RWS最左侧的ACK没有成功发送,重传后收到了RWS最右侧的ACK
385+
386+
**TCP Flow Control**
387+
388+
* Receiver advertises RWS using window field
389+
* Sender can only send data up to LAR+SWS
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‎Notes/Output/C++.md‎

Lines changed: 1 addition & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
11
### C++
22
[toc]
33
#### debug
4-
*[macOS上用VSCode](https://zhuanlan.zhihu.com/p/106935263?utm_source=wechat_session)
4+
[macOS上用VSCode](https://zhuanlan.zhihu.com/p/106935263?utm_source=wechat_session)
55

66
* [CS107 GDB and Debugging教程](https://web.stanford.edu/class/archive/cs/cs107/cs107.1202/resources/gdb)
77
* [CS107 Software Testing Strategies](https://web.stanford.edu/class/archive/cs/cs107/cs107.1202/testing.html)
@@ -13,9 +13,6 @@
1313
* `valgrind`
1414
* `cmake .. -DCMAKE_BUILD_TYPE=Debug` + `gdb`
1515

16-
17-
18-
1916
#### C
2017

2118
* volatile特性:这条代码不要被编译器优化,`volatile int counter = 0`,避免出现意料之外的情况,常用于全局变量
@@ -67,13 +64,11 @@ public:
6764
```
6865
* 类的静态成员函数指针
6966
70-
7167
#### 编程习惯
7268
RAII原则:Resource acquisition is initialization
7369
* [CppCoreGuidelines](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md)
7470
* 用[CppCheck](http://cppcheck.net/)诊断,`make cppcheck`
7571
76-
7772
#### 输入输出
7873
7974
##### 输入用逗号间隔的数据
@@ -129,9 +124,6 @@ sort,自己定义cmp函数,注意cmp的定义:类内静态,传参引用
129124
* map<int,list<pair<int,int>>::iterator> m;
130125
* r.push_front(...), r.begin(), r.back()
131126

132-
##### \<set>
133-
* [multiset用法总结](https://blog.csdn.net/sodacoco/article/details/84798621)
134-
135127
##### \<vector>
136128
* 初始化,可以用列表
137129
* 也可以 `int a[10]={...};vector<int> b(a,a+10); ` 左闭右开
@@ -190,8 +182,6 @@ strcpy(buf, str.c_str());//strncpy(buf, str.c_str(), 10);
190182
* s.fin_first_not_of(s1) 查找s中第一个不属于s1中的字符的位置,并返回(包括0)
191183
* s.fin_last_not_of(s1) 查找s中最后一个不属于s1中的字符的位置,并返回(包括0)
192184
193-
* `basic_string::_M_create`错误:string用两个迭代器初始化第一个比第二个大。
194-
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196186
##### \<sys.h>
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‎Notes/Output/Computer-Networking-Lab-CS144-Stanford.md‎

Lines changed: 33 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -124,7 +124,38 @@ void get_URL(const string &host, const string &path) {
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* <img src="https://raw.githubusercontent.com/huangrt01/Markdown-Transformer-and-Uploader/master/Notes/Computer-Networking-Lab-CS144-Stanford/reassembler.png" alt="reassembler" style="zoom:100%;" />
125125

126126
#### lab2: the TCP receiver
127-
#####
127+
##### 3.1 Sequence Numbers
128+
129+
<img src="https://raw.githubusercontent.com/huangrt01/Markdown-Transformer-and-Uploader/master/Notes/Computer-Networking-Lab-CS144-Stanford/001.jpg" alt="different index" style="zoom:100%;" />
130+
* 利用头文件中的函数简化代码
131+
* 计算出相对checkpoint的偏移量之后,再转化成离checkpoint最近的点,如果加多了就左移,注意返回值太小无法左移的情形。
132+
133+
```c++
134+
uint64_t unwrap(WrappingInt32 n, WrappingInt32 isn, uint64_t checkpoint) {
135+
uint32_t offset = n - wrap(checkpoint, isn);
136+
uint64_t ret = checkpoint + offset;
137+
// 取距离checkpoint最近的值,因此判断的情况是否左移ret
138+
//注意位置不够左移的情形!!!
139+
if (offset >= (1u << 31) && ret >= UINT32_LEN)
140+
ret -= (1ul << 32);
141+
return ret;
142+
}
143+
```
144+
##### 3.2 window
145+
* lower:ackno
146+
* higher~window size
147+
* window size = capacity - ByteStream.buffer_size()
148+
149+
##### 3.3 TCP receiver的实现
150+
1. receive segmentsfrom its peer
151+
2. reassemble the ByteStream using your StreamReassembler, and calculate the
152+
3. acknowledgment number (ackno)
153+
4. and the window size.
154+
155+
* `_reassembler`忽视SYN,所以要手动对index减1、ackno()加1
156+
* 非常规路线的处理:比如对于第二个SYN或者FIN信号,接收机选择忽视,具体见`bool TCPReceiver::segment_received(const TCPSegment &seg)`的实现
157+
158+
128159
129160
130161
#### 工程细节
@@ -140,7 +171,6 @@ string d(size, 0);
140171
generate(d.begin(), d.end(), [&] { return rd(); });
141172
```
142173

143-
144174
* 类cmp函数的定义,适用 `lower_bound()`方法
145175
* 两个**const**都不能掉!
146176
```c++
@@ -152,3 +182,4 @@ class typeUnassembled {
152182
bool operator<(const typeUnassembled &t1) const { return index < t1.index; }
153183
};
154184
```
185+
* `urg = static_cast<bool>(fl_b & 0b0010'0000); // binary literals and ' digit separator since C++14!!!`

‎Notes/Output/Computer-Networking-Lecture-CS144-Stanford.md‎

Lines changed: 37 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -336,7 +336,9 @@ end-to-end check
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<img src="https://raw.githubusercontent.com/huangrt01/Markdown-Transformer-and-Uploader/master/Notes/Computer-Networking-Lecture-CS144-Stanford/013.jpg" alt="TCP Connection" style="zoom:100%;" />
338338

339-
##### 2-7 Flow Control: Stop-and-Wait
339+
* 非常规路线的处理:比如对于第二个SYN或者FIN信号,接收机选择忽视,具体见`bool TCPReceiver::segment_received(const TCPSegment &seg)`的实现
340+
341+
##### 2-7 Flow Control I: Stop-and-Wait
340342
* 核心是receiver给sender反馈,让sender不要送太多packets
341343
* 基本方法
342344
* stop and wait
@@ -351,8 +353,40 @@ end-to-end check
351353
<img src="https://raw.githubusercontent.com/huangrt01/Markdown-Transformer-and-Uploader/master/Notes/Computer-Networking-Lecture-CS144-Stanford/014.jpg" alt="stop-and-wait" style="zoom:100%;" />
352354

353355
##### 2-7 Flow Control II: Sliding Window
354-
355-
356+
* Stop-and-Wait的性能:RTT=50ms, Bottleneck=10Mbps, Ethernet packet length=12Kb => 性能(2%)远远不到瓶颈
357+
* Sliding Window计算Window size填满性能
358+
359+
**Sliding Window Sender**
360+
361+
* Every segment has a sequence number (SeqNo)
362+
* Maintain 3 variables
363+
* Send window size(SWS)
364+
* Last acknowledgment(LAR)
365+
* Last segment sent(LSS)
366+
* Maintain invariant: <img src="https://www.zhihu.com/equation?tex=%28LSS%20-%20LAR%29%20%5Cleq%20SWS" alt="(LSS - LAR) \leq SWS" class="ee_img tr_noresize" eeimg="1">
367+
* Advance LAR on new acknowledgement
368+
* Buffer up to SWS segments
369+
370+
**Sliding Window Receiver**
371+
* Maintain 3 variables
372+
* Receive window size(RWS)
373+
* Last acceptable segment(LAS)
374+
* Last segment received(LSR)
375+
* Maintain invariant: <img src="https://www.zhihu.com/equation?tex=%28LAS%20-%20LSR%29%20%5Cleq%20RWS" alt="(LAS - LSR) \leq RWS" class="ee_img tr_noresize" eeimg="1">
376+
* 如果收到的packet比LAS小,则发送ack
377+
* 发送cumulative acks: 收到1, 2, 3, 5,发送3
378+
* TCP acks are next expected data,因此要加一,上个例子改为4,初值为0
379+
380+
**RWS, SWS, and Sequence Space**
381+
* <img src="https://www.zhihu.com/equation?tex=RWS%20%5Cgeq%201%2C%20SWS%20%5Cgeq%201%2C%20RWS%20%5Cleq%20SWS" alt="RWS \geq 1, SWS \geq 1, RWS \leq SWS" class="ee_img tr_noresize" eeimg="1">
382+
* if <img src="https://www.zhihu.com/equation?tex=RWS%20%3D%201" alt="RWS = 1" class="ee_img tr_noresize" eeimg="1"> , "go back N" protocol ,need SWS+1 sequence numbers (需要多重传)
383+
* if <img src="https://www.zhihu.com/equation?tex=RWS%20%3D%20SWS" alt="RWS = SWS" class="ee_img tr_noresize" eeimg="1"> , need 2SWS sequence numbers
384+
* 通常需要 <img src="https://www.zhihu.com/equation?tex=RWS%2BSWS" alt="RWS+SWS" class="ee_img tr_noresize" eeimg="1"> sequence numbers:考虑临界情况,RWS最左侧的ACK没有成功发送,重传后收到了RWS最右侧的ACK
385+
386+
**TCP Flow Control**
387+
388+
* Receiver advertises RWS using window field
389+
* Sender can only send data up to LAR+SWS
356390

357391

358392

‎README.md‎

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Original file line numberDiff line numberDiff line change
@@ -38,7 +38,7 @@
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#### [Stanford-CS144-Lecture](https://github.com/huangrt01/CS-Notes/blob/master/Notes/Output/Computer-Networking-Lecture-CS144-Stanford.md)■しかく■しかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく
4040

41-
#### [Stanford-CS144-Lab](https://github.com/huangrt01/CS-Notes/blob/master/Notes/Output/Computer-Networking-Lab-CS144-Stanford.md)■しかく■しかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく
41+
#### [Stanford-CS144-Lab](https://github.com/huangrt01/CS-Notes/blob/master/Notes/Output/Computer-Networking-Lab-CS144-Stanford.md)■しかく■しかく■しかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく
4242

4343
#### [Computer-Networking-A-Top-Down-Approach](https://github.com/huangrt01/CS-Notes/blob/master/Notes/Output/Computer-Networking-A-Top-Down-Approach.md)□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく□しろいしかく
4444

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