Question

I am trying to solve the following introductory POSIX Sockets exercise:

笔录

(我假定“制度”是指本组织。)

我不理解的是,如果连接(如果我不正确的话)以上述方式履行约束义务,那么(如果我不正确的话,我就认为)要求是必需的。而且,为了向要求完成这种行为的受约束者提供袖珍地址,还需要什么价值——第6号——补充和第6号——?

Answer 1

您是正确的,无需打bind。该系统将在<条码>联接/代码>时选择源地址和源港。页: 1

这是一项工作。它只是检验你是否知道如何使用<条码>bind。

Answer 2

I do not understand why a bind() call is necessary when connect() performs the bind in the aforementioned way (correct me if I am incorrect).

你是正确的。

Also, what values of sin6_addr and sin6_port are necessary for the socket address provided to the bind() call to accomplish this behavior?

INADDR_ANY for IPv4. 我将把IPv6作为读者的一种做法。

You should also specify zero as the port number, then the system will choose.

Answer 3

EDIT:这与所要求的情况相反。我认为,问题在于用户<>选择IP地址和港口。由于欧洲司法论坛指出了这一点。

This should be what you re looking for.

这应当是最有意义的部分:

clnt_addr.sin_family = AF_INET; clnt_addr.sin_addr.s_addr = INADDR_ANY; clnt_addr.sin_port = htons(33333); if (bind(sockfd, (struct sockaddr *) &clnt_addr, sizeof(clnt_addr)) < 0) error("ERROR on binding");

举例来说,在连接之前,单列单只与预期港口(33333)有关,但在你看来,你可以将上述代码第二行改为:

clnt_addr.sin_addr.s_addr = inet_addr("192.168.0.1");

to have the socket bound also on a specific IP address. What matters here is that binding the socket before the connect() sets your endpoint of the TCP/IP communication to use the desired IP address/port. Without the bind() your socket would have been unbounded: the kernel would have chosen the source IP address for you and would have assigned a random source port to your socket.

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