xref: /openbmc/libpldm/src/transport/socket.c (revision f89befe3ef7bfc8efc139711e5bc27bdc08502e0)
1 #include "socket.h"
2 
3 #include <errno.h>
4 #include <limits.h>
5 #include <stddef.h>
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <sys/socket.h>
9 
10 int pldm_socket_sndbuf_init(struct pldm_socket_sndbuf *ctx, int socket)
11 {
12 	FILE *fp;
13 	long max_buf_size;
14 	char line[128];
15 	char *endptr;
16 
17 	if (socket == -1) {
18 		return -1;
19 	}
20 	ctx->socket = socket;
21 
22 	fp = fopen("/proc/sys/net/core/wmem_max", "r");
23 	if (fp == NULL || fgets(line, sizeof(line), fp) == NULL) {
24 		fclose(fp);
25 		return -1;
26 	}
27 
28 	errno = 0;
29 	max_buf_size = strtol(line, &endptr, 10);
30 	if (errno != 0 || endptr == line) {
31 		fclose(fp);
32 		return -1;
33 	}
34 
35 	fclose(fp);
36 
37 	if (max_buf_size > INT_MAX) {
38 		max_buf_size = INT_MAX;
39 	}
40 	ctx->max_size = (int)max_buf_size;
41 
42 	if (pldm_socket_sndbuf_get(ctx)) {
43 		return -1;
44 	}
45 
46 	return 0;
47 }
48 
49 int pldm_socket_sndbuf_accomodate(struct pldm_socket_sndbuf *ctx, int msg_len)
50 {
51 	if (msg_len < ctx->size) {
52 		return 0;
53 	}
54 	/* If message is bigger than the max size, don't return a failure. Set
55 	 * the buffer to the max size and see what happens. We don't know how
56 	 * much of the extra space the kernel actually uses so let it tell us if
57 	 * there wasn't enough space */
58 	if (msg_len > ctx->max_size) {
59 		msg_len = ctx->max_size;
60 	}
61 	if (ctx->size == ctx->max_size) {
62 		return 0;
63 	}
64 	int rc = setsockopt(ctx->socket, SOL_SOCKET, SO_SNDBUF, &(msg_len),
65 			    sizeof(msg_len));
66 	if (rc == -1) {
67 		return -1;
68 	}
69 	ctx->size = msg_len;
70 	return 0;
71 }
72 
73 int pldm_socket_sndbuf_get(struct pldm_socket_sndbuf *ctx)
74 {
75 	/* size returned by getsockopt is the actual size of the buffer - twice
76 	 * the size of the value used by setsockopt. So for consistency, return
77 	 * half of the buffer size */
78 	int buf_size;
79 	socklen_t optlen = sizeof(buf_size);
80 	int rc = getsockopt(ctx->socket, SOL_SOCKET, SO_SNDBUF, &(buf_size),
81 			    &optlen);
82 	if (rc == -1) {
83 		return -1;
84 	}
85 	ctx->size = buf_size / 2;
86 	return 0;
87 }
88